Tarasco has great suggestions, though for Brion I would recommend Miren over High Market since you can gain significantly more life (also, it is cheaper).
For the strategy you are going for I would recommend adding cards like Preacher/Evangelize, Conquering Manticore and Mass Mutiny. If you're ok with some more random or inconsistent elements try Illicit Auction and Debt of Loyalty. I will point out here that the strategy you're looking for with threaten effects has a lot of promise for a Brion Stoutarm deck but you will need to tone down your average CMC to make it more viable.
Two last quick notes before I finish. First, it may be in your best interest to remove some of your board wipes. If you play in a hardcore group where the wipes are your only real contribution to a game then ignore this but if you play casually tone it down. A good rule of thumb is to have two mass removal (and a bunch of single target removal) spells in your deck. If everyone at the table in a four player game runs more than that the game degenerates quickly.
This list is kind of all over the place. I can't really see a clearly defined game plan outside of big flashy creatures and good stuff effects. Thing is, I don't think these cards have the support cards to do this as effectively as other color combinations. You're going to have to work out an effective strategy that can win, has a good amount of resilience to disruption, and is fairly consistent. For these colors that can be a tall order. That doesn't mean I can't make suggestions. Sorry about the infodump.
More awesome instants are required: Chaos Warp, Path to Exile, Swords to Plowshares, Enlightened Tutor, Oblation, Return to Dust, Tithe, Wild Ricochet, Grab the Reins. There are more, but I think these are the best. All of these deserve a spot in this list. All of them will get you dirty looks with Sunforger. I seriously don't think this color combination can be competitive without them.
I realize card draw is hard to come by in these colors, but I still wouldn't run Howling Mine type effects. Often times I have to resort to card combos to get any sort of card adv engines going, but Mind's Eye is probably the best card you can hope for in these situations. Sadly, it makes you a target, but a reasonable table will acknowledge that and white just don't have a lot of options in this regard. They'll take sympathy on you. And that's when you'll play a 30/30 Serra Avatar and have Brion shove it down their throats. (That last comment is purely rhetorical. Don't play Serra Avatar. Creatures need to do more than just attack and defend).
Skullclamp is a great here for drawing cards, if you pair it with some sort of token producer. Land Tax and Scroll Rack can work together to keep your hand full. If you go for an equipment theme, which is pretty much the only strat I like in these colors, Puresteel Paladin draws you cards for playing your deck. Consider also Memory Jar, Wheel of Fortune, and Reforge the Soul. You may not always be able to hog the benefit for yourself, but you tend to get more out of them than everyone else, especially with Memory Jar, and they can disrupt combo players who have shrewdly been crafting their hands all game.
Tutors equal consistency. Some people hate them, and feel they violate the spirit of format. I tend to think they are a crux of good deck building and that certain colors especially red and white cannot consistently function without them. Land Tutors: Weathered Wayfairer, Tithe, Expedition Map. In addition to making sure you hit all of your land drops, all of these grab non-basic lands which is useful if you need haste enablers like Slayers Stronghold, or sac outlets like Miren, the Moaning Well. Land Tax may only grab basic lands but its still awesome at ensuring land drops and well worth considering.
Equipment Tutors: Enlightened Tutor, Stoneforge Mystic, Stonehewer Giant, Steelshaper's Gift, Godo, Bandit Warlord, Taj-Nar Swordsmith. Aside from Brion, attacking is pretty much the only option the deck has to wrap up games. Equipment cards are big assets here and white seems to specialize in fetching them alongside great cards like Godo. They give creatures protection from removal, enemy blockers, and sometimes give them crazy abilities (Like Sunforger, which you're already playing). They make non-threatening utility creatures into decent threats by their own, and can work together to make them monsters. Some of them do several things at one. Nim Deathmantle is a reusable recursion engine (albeit an expensive one), a creature pump, and an evasion enabler. The card is worth like fifty-cents. I love it. Cards with the living weapon ability are basically tutorable creatures. The better equipment cards are more expensive, the best sword options, Sword of Fire and Ice and Sword of Feast and Famine, are expensive enough I wouldn't go out buying one unless you have other places you can use them.
Sunforger itself is a crazy powerful tutor effect that can terrorize the board into defeat if left unchecked. The cost of constantly equipping it is steep without the help of cards like Puresteel Paladin, but its versatility is nigh unparalleled.
Gamble and Planar Portal are the only unconditional tutors I know of in these colors and you can see they are not without their drawbacks. I'm trying to think of other kinds of tutors but I'm drawing a blank.
Recursion is another thing to consider when trying to improve deck consistency. Being able to get back lost creatures and artifacts from the bin, adds a whole new dimension of attack to your resources. White specializes in creature recursion: Karmic Guide, Reveillark, and Sun Titan, are popular choices and among the most powerful cards in these roles. Adarkar Valkyrie is a awesome board protector whose ability can also be used to steal opponents' creatures as well. Some people like Reya Dawnbringer here but to be honest, I've never managed to untap with her still in play. Misc recursion: Mistveil Plains, reuse instants with sunforger, or any other conceivable tutor target. It hits everything, and carries the plains land type, so it can be tutored by fetchlands, tithe, and Flagstones of Trokair.
For artifact recursion, you have a few options in both colors. White has Argivian Archaeologist[/CARD] and Argivian Find. Red has Goblin Welder. Goblin Welder is insane, and Argivian Archaeologist isn't too far behind. Between the two of them nothing you lose will stay gone for long. For land Recursion I'm afraid the only viable answer is Crucible of Worlds, another walletslayer. Played along cards like Wasteland and Strip Mine, it does support the mass LD strat I'm noticing in your list of sorceries. Consider carefully, the competitive level of the table before playing anything this douche-y, it can create unfun board states. If you do run Crucible, consider running Buried Ruin also, because the two actually protect one another with minimal invest from you.
Looking at your sorceries I'm noting you have no qualms about mass land destruction, which is fine. Dropping a decent threat and then wiping lands is perhaps the cleanest path to victory you can hope for. Apocalypse and Jokulhaups worry me though. Without an indestructible creature or some kind of recursion that doesn't require mana for activation you have no clear way of winning the game post resolution. Apocalypse is even worse because it forces you (and only you) to start top decking and hope that you find something that can win the game, which is unlikely at best. Check out, Boom//Bust, Keldon Firebombers, Impending Disaster, Decree of Annihilation (Don't. Hardcast. This.), and Ravages of War (!!!). I see Day of Judgment and Catastrophe here but I think you need more wrath spells. I'd run Hallowed Burial, Austere Command, because of the later is a versatile solution to just about any board position, and the former because it is the most final solution to creature based threats. Insurrection?
Next are the cards I'd cut. Most of these are selvected because I think they're too narrow, or their effects too weak. I'll make some comments on them regardless.
Instants
- Smite the Monstrous, Rebuke, Lightning Helix: These removal spells are outclassed by cards like Path to Exile and Swords to Plowshares, I list Rebuke and not Condemn here because condemn places cards on the bottom of their decks, a place from which it is unlikely they will ever return without direct intervention from the player in the form of a tutor spell. Condemn also cost a single white mana. There really is no contest.
- Reverberate: Outclassed by Wild Ricochet, plain and simple.
- Congregate: Lifegain for lifegain's sake is rarely worth the cardboard its printed on, but Congregate is one of the most powerful lifegain spells ever printed and thus deserves more respect. Congregate really shines in decks where you and everyone else has a lot of creatures, and more often than not, the caster of congregate has some way of taking the abstraction of their life total and transmuting it into a bludgeoning weapon of sorts. You don't have the token generation to make this card truly degenerate. You've got Serra Avatar in the list, but she will almost never connect with an actual opponent, and attack, blocking, and getting sacc'd by Brion is the only thing she and Malignus do. Rather than adding cards to make this playable, why not just drop it and give the slot to something more relevant.
Sorceries
- Metallic Mastery, Traitorous Blood, Act of Treason: An above poster mentioned conquering masticore, grab the reins (sunforger target), and Act of Aggression, use those.
- Wrack with Madness: Better creature removal options mentioned above.
- Jokulhaups, Apocalypse: Mentioned above
- Remember the Fallen, Breath of Life: Better Recursion options mentioned above.
Enchantments
- Curse of Bloodletting: I can understand wanting some kind of redundancy with Gisela, but first I don't think its necessary, and second Furnace of Rath does it better.
- Story Circle: This is a bandaid to a symptom, not a solution to a problem. Way too many creatures attacking you? Run more Wrath of God effects. Too much non-combat damage? Run player shroud effects like True Believer, Ivory Mask, Leyline or Sanctity, and Imperial Mask. These cards can shut certain generals or strategies down completely.
- Nevermore: I've had a need to run this, but this card is totally a meta decision and its value depends entirely upon your playgroup.
Artifacts
- Howling Mine: Mentioned above. No one will fault you for being stingy with the cards
- Venser's Journal: I'm doubtful you will ever have a hand size large enough to justify including this card.
- Traveler's Amulet: Works better as Expedition Map or Wayfairer's Bauble. The latter actually puts the land into play.
Creatures (You've got Tyrant of Discord on here twice)
- Fire Servant: Lightning Helix, Wrack with Madness, and Ajani Vengeant are the only cards you play that interact with this card.
- Tyrant of Discord: Far too random for its cost.
- Charmbreaker Devils: As your list is now, I'm not sure you play enough instants and sorceries to include this. I've got nothing against the card though.
- Archwing Dragon: There are far better options. This is essentially a four mana sorcery speed burn spell that your opponent can chose to block or kill.
- Chartooth Cougar, Serra Avatar, Serra Angel, Gideon's Avenger, Malignus: In the whole library of red and white creature spells vanilla attackers/blockers are underwhelming unless they're Figure of Destiny or Serra Ascendant levels of insane or they're really hard to kill, like the two Akroma's.
- Rage Thrower: At six mana, you can do than this.
- Leonin Relic-Warder: Chaos Warp, Oblation, Return to Dust, are Disenchant are more permanent solutions for problematic artifacts and enchantments, and all of those are sunforger targets.
1 x Brion Stoutarm
1 x Firemane Angel
1 x Gisela, Blade of Goldnight
1 x Figure of Destiny
1 x Galvanoth
1 x Fire Servant
1 x Tyrant of Discord
1 x Charmbreaker Devils
1 x Archwing Dragon
1 x Chartooth Cougar
1 x Hellkite Charger
1 x Malignus
1 x Zealous Conscripts
1 x Balefire Liege
1 x Rage Thrower
1 x Tyrant of Discord
1 x Archon of Justice
1 x Serra Avatar
1 x Serra Angel
1 x Gideon's Avenger
1 x Nearheath Pilgrim
1 x Leonin Relic-Warder
1 x Rune-Tail, Kitsune Ascendant
1 x Serra Ascendant
1 x Angelic Arbiter
1 x Howling Mine
1 x Sphere of the Suns
1 x Mimic Vat
1 x Sol Ring
1 x Manalith
1 x Sunforger
1 x Vessel of Endless Rest
1 x Conjurer's Closet
1 x Venser's Journal
1 x Lightning Greaves
1 x Well of Lost Dreams
1 x Traveler's Amulet
1 x Pristine Talisman
Planeswalkers
1 x Ajani Vengeant
1 x Ajani Goldmane
1 x Gideon Jura
1 x Smith the Monstrous
1 x Rebuke
1 x Congregate
1 x Lightning Helix
1 x Condemn
1 x Reverberate
1 x Metallic Mastery
1 x Traitorous Blood
1 x Day of Judgment
1 x Catastrophe
1 x Act of Treason
1 x Wrack with Madness
1 x Armageddon
1 x Jokulhaups
1 x Remember the Fallen
1 x Breath of Life
1 x Apocalypse
1 x Nevermore
1 x Splinter Twin
1 x Story Circle
1 x Evolving Wilds
1 x Arid Mesa
1 x Haunted Fengraf
1 x Slayers' Stronghold
1 x Clifftop Retreat
1 x Shimmering Grotto
1 x Terramorphic Expanse
15 x Mountain
15 x Plains
My goal is to gain life, steal things and throw them, or steal them and keep them with [CARD]Conjurer's Closet[CARD]
Any advice will be appreciated!
Thank you!
Enlightened Tutor can help you get what you need most of the time. And if you're going the life gain route, Felidar Sovereign deserves a look. High Market isn't a bad sac outlet.
Not a big fac of Congregate. I would probably replace it with Angelic Chorus. Cradle of Vitality and True Conviction are also worth a shot.
Most recently looking at Morinfen!
For the strategy you are going for I would recommend adding cards like Preacher/Evangelize, Conquering Manticore and Mass Mutiny. If you're ok with some more random or inconsistent elements try Illicit Auction and Debt of Loyalty. I will point out here that the strategy you're looking for with threaten effects has a lot of promise for a Brion Stoutarm deck but you will need to tone down your average CMC to make it more viable.
Two last quick notes before I finish. First, it may be in your best interest to remove some of your board wipes. If you play in a hardcore group where the wipes are your only real contribution to a game then ignore this but if you play casually tone it down. A good rule of thumb is to have two mass removal (and a bunch of single target removal) spells in your deck. If everyone at the table in a four player game runs more than that the game degenerates quickly.
EDIT: Forgot to add that you may want to consider some of the instant speed threaten effects like Grab the Reins, Act of Aggression and Blind with Anger.
GW Aggro
EDH:
BUG Damia Landfall
RW [Primer] Brion Stoutarm
R Bosh's Bash
More awesome instants are required: Chaos Warp, Path to Exile, Swords to Plowshares, Enlightened Tutor, Oblation, Return to Dust, Tithe, Wild Ricochet, Grab the Reins. There are more, but I think these are the best. All of these deserve a spot in this list. All of them will get you dirty looks with Sunforger. I seriously don't think this color combination can be competitive without them.
I realize card draw is hard to come by in these colors, but I still wouldn't run Howling Mine type effects. Often times I have to resort to card combos to get any sort of card adv engines going, but Mind's Eye is probably the best card you can hope for in these situations. Sadly, it makes you a target, but a reasonable table will acknowledge that and white just don't have a lot of options in this regard. They'll take sympathy on you. And that's when you'll play a 30/30 Serra Avatar and have Brion shove it down their throats. (That last comment is purely rhetorical. Don't play Serra Avatar. Creatures need to do more than just attack and defend).
Skullclamp is a great here for drawing cards, if you pair it with some sort of token producer. Land Tax and Scroll Rack can work together to keep your hand full. If you go for an equipment theme, which is pretty much the only strat I like in these colors, Puresteel Paladin draws you cards for playing your deck. Consider also Memory Jar, Wheel of Fortune, and Reforge the Soul. You may not always be able to hog the benefit for yourself, but you tend to get more out of them than everyone else, especially with Memory Jar, and they can disrupt combo players who have shrewdly been crafting their hands all game.
Tutors equal consistency. Some people hate them, and feel they violate the spirit of format. I tend to think they are a crux of good deck building and that certain colors especially red and white cannot consistently function without them. Land Tutors: Weathered Wayfairer, Tithe, Expedition Map. In addition to making sure you hit all of your land drops, all of these grab non-basic lands which is useful if you need haste enablers like Slayers Stronghold, or sac outlets like Miren, the Moaning Well. Land Tax may only grab basic lands but its still awesome at ensuring land drops and well worth considering.
Equipment Tutors: Enlightened Tutor, Stoneforge Mystic, Stonehewer Giant, Steelshaper's Gift, Godo, Bandit Warlord, Taj-Nar Swordsmith. Aside from Brion, attacking is pretty much the only option the deck has to wrap up games. Equipment cards are big assets here and white seems to specialize in fetching them alongside great cards like Godo. They give creatures protection from removal, enemy blockers, and sometimes give them crazy abilities (Like Sunforger, which you're already playing). They make non-threatening utility creatures into decent threats by their own, and can work together to make them monsters. Some of them do several things at one. Nim Deathmantle is a reusable recursion engine (albeit an expensive one), a creature pump, and an evasion enabler. The card is worth like fifty-cents. I love it. Cards with the living weapon ability are basically tutorable creatures. The better equipment cards are more expensive, the best sword options, Sword of Fire and Ice and Sword of Feast and Famine, are expensive enough I wouldn't go out buying one unless you have other places you can use them.
Sunforger itself is a crazy powerful tutor effect that can terrorize the board into defeat if left unchecked. The cost of constantly equipping it is steep without the help of cards like Puresteel Paladin, but its versatility is nigh unparalleled.
Gamble and Planar Portal are the only unconditional tutors I know of in these colors and you can see they are not without their drawbacks. I'm trying to think of other kinds of tutors but I'm drawing a blank.
Recursion is another thing to consider when trying to improve deck consistency. Being able to get back lost creatures and artifacts from the bin, adds a whole new dimension of attack to your resources. White specializes in creature recursion: Karmic Guide, Reveillark, and Sun Titan, are popular choices and among the most powerful cards in these roles. Adarkar Valkyrie is a awesome board protector whose ability can also be used to steal opponents' creatures as well. Some people like Reya Dawnbringer here but to be honest, I've never managed to untap with her still in play. Misc recursion: Mistveil Plains, reuse instants with sunforger, or any other conceivable tutor target. It hits everything, and carries the plains land type, so it can be tutored by fetchlands, tithe, and Flagstones of Trokair.
For artifact recursion, you have a few options in both colors. White has Argivian Archaeologist[/CARD] and Argivian Find. Red has Goblin Welder. Goblin Welder is insane, and Argivian Archaeologist isn't too far behind. Between the two of them nothing you lose will stay gone for long. For land Recursion I'm afraid the only viable answer is Crucible of Worlds, another walletslayer. Played along cards like Wasteland and Strip Mine, it does support the mass LD strat I'm noticing in your list of sorceries. Consider carefully, the competitive level of the table before playing anything this douche-y, it can create unfun board states. If you do run Crucible, consider running Buried Ruin also, because the two actually protect one another with minimal invest from you.
Looking at your sorceries I'm noting you have no qualms about mass land destruction, which is fine. Dropping a decent threat and then wiping lands is perhaps the cleanest path to victory you can hope for. Apocalypse and Jokulhaups worry me though. Without an indestructible creature or some kind of recursion that doesn't require mana for activation you have no clear way of winning the game post resolution. Apocalypse is even worse because it forces you (and only you) to start top decking and hope that you find something that can win the game, which is unlikely at best. Check out, Boom//Bust, Keldon Firebombers, Impending Disaster, Decree of Annihilation (Don't. Hardcast. This.), and Ravages of War (!!!). I see Day of Judgment and Catastrophe here but I think you need more wrath spells. I'd run Hallowed Burial, Austere Command, because of the later is a versatile solution to just about any board position, and the former because it is the most final solution to creature based threats. Insurrection?
Next are the cards I'd cut. Most of these are selvected because I think they're too narrow, or their effects too weak. I'll make some comments on them regardless.
Instants
- Smite the Monstrous, Rebuke, Lightning Helix: These removal spells are outclassed by cards like Path to Exile and Swords to Plowshares, I list Rebuke and not Condemn here because condemn places cards on the bottom of their decks, a place from which it is unlikely they will ever return without direct intervention from the player in the form of a tutor spell. Condemn also cost a single white mana. There really is no contest.
- Reverberate: Outclassed by Wild Ricochet, plain and simple.
- Congregate: Lifegain for lifegain's sake is rarely worth the cardboard its printed on, but Congregate is one of the most powerful lifegain spells ever printed and thus deserves more respect. Congregate really shines in decks where you and everyone else has a lot of creatures, and more often than not, the caster of congregate has some way of taking the abstraction of their life total and transmuting it into a bludgeoning weapon of sorts. You don't have the token generation to make this card truly degenerate. You've got Serra Avatar in the list, but she will almost never connect with an actual opponent, and attack, blocking, and getting sacc'd by Brion is the only thing she and Malignus do. Rather than adding cards to make this playable, why not just drop it and give the slot to something more relevant.
Sorceries
- Metallic Mastery, Traitorous Blood, Act of Treason: An above poster mentioned conquering masticore, grab the reins (sunforger target), and Act of Aggression, use those.
- Wrack with Madness: Better creature removal options mentioned above.
- Jokulhaups, Apocalypse: Mentioned above
- Remember the Fallen, Breath of Life: Better Recursion options mentioned above.
Enchantments
- Curse of Bloodletting: I can understand wanting some kind of redundancy with Gisela, but first I don't think its necessary, and second Furnace of Rath does it better.
- Story Circle: This is a bandaid to a symptom, not a solution to a problem. Way too many creatures attacking you? Run more Wrath of God effects. Too much non-combat damage? Run player shroud effects like True Believer, Ivory Mask, Leyline or Sanctity, and Imperial Mask. These cards can shut certain generals or strategies down completely.
- Nevermore: I've had a need to run this, but this card is totally a meta decision and its value depends entirely upon your playgroup.
Artifacts
- Howling Mine: Mentioned above. No one will fault you for being stingy with the cards
- Venser's Journal: I'm doubtful you will ever have a hand size large enough to justify including this card.
- Traveler's Amulet: Works better as Expedition Map or Wayfairer's Bauble. The latter actually puts the land into play.
Creatures (You've got Tyrant of Discord on here twice)
- Fire Servant: Lightning Helix, Wrack with Madness, and Ajani Vengeant are the only cards you play that interact with this card.
- Tyrant of Discord: Far too random for its cost.
- Charmbreaker Devils: As your list is now, I'm not sure you play enough instants and sorceries to include this. I've got nothing against the card though.
- Archwing Dragon: There are far better options. This is essentially a four mana sorcery speed burn spell that your opponent can chose to block or kill.
- Chartooth Cougar, Serra Avatar, Serra Angel, Gideon's Avenger, Malignus: In the whole library of red and white creature spells vanilla attackers/blockers are underwhelming unless they're Figure of Destiny or Serra Ascendant levels of insane or they're really hard to kill, like the two Akroma's.
- Rage Thrower: At six mana, you can do than this.
- Leonin Relic-Warder: Chaos Warp, Oblation, Return to Dust, are Disenchant are more permanent solutions for problematic artifacts and enchantments, and all of those are sunforger targets.
Note about lands: there are a fair amount of duals and multicolored lands that can hit both of your colors here. Command Tower, Reflecting Pool, City of Brass, etc. Also you can run all the fetchlands you want because they don't show mana symbols in their card text and don't tap for colored mana. Bloodstained Mire, Marsh Flats, Windswept Heath, Flooded Strand, Scalding Tarn, and Wooded Foothills, could all find a place in this deck. Utility lands worth considering: Hall of the Bandit Lord, Sunholme, Fortress of the Legion, Shinka, the Bloodsoaked Keep, and Kor Haven.
Oh Rider, my heart will go on...