This is a modified version of RDW/UR Phoenix I came up with (I'm sure I'm not the first, but I couldn't find a comparable thread). A strictly worse (budget) version of this deck I've been running on Arena has pretty much lifted me to Gold 1 over the last couple weeks, the complete version is probably just as good as the established decks in the format.
Why should you play this deck instead of RDW or UR Pheonix?
Pros: BR Phoenix is a more consistent, is more resilient, and is has more card advantage than RDW and is faster and more explosive than UR Phoenix. Playing a fast deck on Arena is good because you get more games in, so it takes less time to rank up.
Cons: A little slower than RDW (a good match up if their initial draw isn't fantastic because you usually win if you can outlast them), and less card advantage than UR Phoenix.
The primary goal of the deck is to get an Arclight Phoenix or two in the grave, play 3 spells and swing until your opponent concedes or their life hits 0. Another way to win is to get Guttersnipe out, and start cycling through your deck with Crash Through and Warlord's Fury. If Guttersnipe stays on board, it almost guarantees victory for you because it acts like a powerful engine taking on 2 damage to all of your spells (which can add up to a lot with The Flame of Keld out, or when you can play 4-5 spells per turn, but it dies to almost all removal. It's a good idea to play Guttersnipe later in the game when your opponent's removal has already been used on your other creatures, maybe when you have 4-5 mana (and a couple cheap spells in hand to play in response to removal).
Most of the cards are pretty standard in RDW. Runaway Steam-Kin is better in this deck, because not only can it become a beefy creature, it can give you the extra mana you need to get to 3 pre-combat spells or to feed your Guttersnipe. With Steam-Kin and Guttersnipe in play, this deck feels more like a combo deck/engine when you play it given how quickly you can cycle through your deck.
Warlord's Fury and (less so) Crash Through have relevant abilities, but if your opponent isn't paying attention (and you play fast) often times they forget that your creatures have first strike since the spells are mainly used as cantrips for you. ~25% of the time, you can get a free creature because your opponent forgot that your creatures have first strike and made poor blocks.
Carnival // Carnage hits all the 1-toughness creatures in the format and turns on spectate. Against control, you can Blightning them.
The sideboard should have Duress or Drill Bit for control match ups and vs gates since Gates Ablaze is the only card that beats us, and the rest really depends on your meta-game and matchups.
All warfare is based on deception. Hence, when we are able to attack, we must seem unable; when using our forces, we must appear inactive; when we are near, we must make the enemy believe we are far away; when far away, we must make him believe we are near.
~The Art of War
This deck is a combo deck designed around disguising your intentions. It's made primarily for MTG Arena, but you can use it in BO3 games as well.
Let's start out with what I think is the strongest version, 1, the Wizard version.
The idea behind this deck is to make your opponent discard their removal/major threats, and either win using your lifegain via tempo vs creature decks and aggro, and vs control you want to use your discard, counter magic and Dawn of Hope to grind out a win. Usually you're playing Mastermind's Acquisition to grabOn Serra's Wings from the sideboard. Sorcerer's Wand can be a win con and help us eek out a victory (since you can re-equip it multiple times a turn with enough mana) if there's a stalled board. Raff Capashen, Ship's Mage lets us play our other combo pieces at instant speed. I'd run 20-25 lands, with a low curve.
In theory, this deck has a lot of good match-ups. Targeted discard like Duress is powerful vs control and vs burn. Control plays so many lands, when you take one or two of their best cards away, not only do you get to peak at their hand, you also make their draw worse since you make the distribution of cards in their hand more land heavy. Aggro/RDW. Both these deck types are played heavily on MTG Arena. Decks like gates don't really have any targeted removal, so as long as you make them discard or counter Gate's Ablaze, you should be able to combo off. Since our combo is infinite, other life gain decks aren't really a problem for us either, which is another common deck on Arena. Senate Guildmage lets us untap Famished Paladin, triggers Dawn of Hope and puts counters on Ajani's Pridemate
This is mostly preference, I like Pilfering Imp because it can be recurred with either Ajani, Adversary of Tyrants or Isareth the Awakener. Drill Bit is good with graveyard-matters cards. Thought Erasure can grab creatures too (unlike duress) and helps you search for combo pieces.
What's left for this deck? It needs tuning for sure, and there are a lot of routes to go into. The best thing you can do is choose a theme and focus on that more than I currently am, but that comes down to your play-style and preferences.
The BW Lifegain version would probably focus more on Vampires, and I'll leave adapting someone else's list as an exercise to the reader (probably moving Sorcerer's Wand to the sideboard and bringing in On Serra's Wings. Remember that life-gain that doesn't do anything else isn't super useful, which is an important reason to leave out more "pure" life gain cards.
Why should you play this deck instead of RDW or UR Pheonix?
Pros: BR Phoenix is a more consistent, is more resilient, and is has more card advantage than RDW and is faster and more explosive than UR Phoenix. Playing a fast deck on Arena is good because you get more games in, so it takes less time to rank up.
Cons: A little slower than RDW (a good match up if their initial draw isn't fantastic because you usually win if you can outlast them), and less card advantage than UR Phoenix.
Okay, enough yappin, to the deck!
BR Phoenix Main Deck
4 Crash Through
4 Warlord's Fury
4 Ghitu Lavarunner
4 Shock
2 Lava Coil
4 Runaway Steam-Kin
3 Rix Maadi Reveler
3 The Flame of Keld
4 Light Up the Stage
1 Skewer the Critics
2 Guttersnipe
2 Risk Factor
4 Arclight Phoenix
4 Dragonskull Summit
2 Blood Crypt
11 Mountain
The primary goal of the deck is to get an Arclight Phoenix or two in the grave, play 3 spells and swing until your opponent concedes or their life hits 0. Another way to win is to get Guttersnipe out, and start cycling through your deck with Crash Through and Warlord's Fury. If Guttersnipe stays on board, it almost guarantees victory for you because it acts like a powerful engine taking on 2 damage to all of your spells (which can add up to a lot with The Flame of Keld out, or when you can play 4-5 spells per turn, but it dies to almost all removal. It's a good idea to play Guttersnipe later in the game when your opponent's removal has already been used on your other creatures, maybe when you have 4-5 mana (and a couple cheap spells in hand to play in response to removal).
Most of the cards are pretty standard in RDW. Runaway Steam-Kin is better in this deck, because not only can it become a beefy creature, it can give you the extra mana you need to get to 3 pre-combat spells or to feed your Guttersnipe. With Steam-Kin and Guttersnipe in play, this deck feels more like a combo deck/engine when you play it given how quickly you can cycle through your deck.
Rix Maadi Reveler, Risk Factor and The Flame of Keld (Tormenting Voice works here too) all let you pitch extra lands, The Flame of Kelds and Arclight Phoenixs, along with refilling your hand with gas.
Warlord's Fury and (less so) Crash Through have relevant abilities, but if your opponent isn't paying attention (and you play fast) often times they forget that your creatures have first strike since the spells are mainly used as cantrips for you. ~25% of the time, you can get a free creature because your opponent forgot that your creatures have first strike and made poor blocks.
Carnival // Carnage hits all the 1-toughness creatures in the format and turns on spectate. Against control, you can Blightning them.
The sideboard should have Duress or Drill Bit for control match ups and vs gates since Gates Ablaze is the only card that beats us, and the rest really depends on your meta-game and matchups.
This deck is a combo deck designed around disguising your intentions. It's made primarily for MTG Arena, but you can use it in BO3 games as well.
The combo we're building around is:
Famished Paladin + On Serra's Wings or Squire's Devotion + Sorcerer's Wand
There are a few different versions of this deck:
1. a (BUW/UW) Wizard theme
2. a (BUW/UW) Control theme
3. a (BW)Lifegain deck
Let's start out with what I think is the strongest version, 1, the Wizard version.
The idea behind this deck is to make your opponent discard their removal/major threats, and either win using your lifegain via tempo vs creature decks and aggro, and vs control you want to use your discard, counter magic and Dawn of Hope to grind out a win. Usually you're playing Mastermind's Acquisition to grabOn Serra's Wings from the sideboard. Sorcerer's Wand can be a win con and help us eek out a victory (since you can re-equip it multiple times a turn with enough mana) if there's a stalled board. Raff Capashen, Ship's Mage lets us play our other combo pieces at instant speed. I'd run 20-25 lands, with a low curve.
In theory, this deck has a lot of good match-ups. Targeted discard like Duress is powerful vs control and vs burn. Control plays so many lands, when you take one or two of their best cards away, not only do you get to peak at their hand, you also make their draw worse since you make the distribution of cards in their hand more land heavy. Aggro/RDW. Both these deck types are played heavily on MTG Arena. Decks like gates don't really have any targeted removal, so as long as you make them discard or counter Gate's Ablaze, you should be able to combo off. Since our combo is infinite, other life gain decks aren't really a problem for us either, which is another common deck on Arena. Senate Guildmage lets us untap Famished Paladin, triggers Dawn of Hope and puts counters on Ajani's Pridemate
Wizard Theme, Main Deck
4 Pilfering Imp
2 Thought Erasure
3 Senate Guildmage
4 Ajani's Pridemate
3 Dawn of Hope
3 Famished Paladin
2 Moment of Craving
2 Isareth the Awakener
3 Ajani, Adversary of Tyrants
2 Raff Capashen, Ship's Mage
3 Mastermind's Acquisition
1 Island
4 Watery Grave
4 Hallowed Fountain
3 Godless Shrine
3 Drowned Catacomb
4 Glacial Fortress
3 Isolated Chapel
Wizard Theme, Sideboard:
2 Siren Stormtamer
3 On Serra's Wings
2 Squire's Devotion
4 Duress
3 Spell Pierce
Let's run through some of the card choices for this deck
Discard:
This is mostly preference, I like Pilfering Imp because it can be recurred with either Ajani, Adversary of Tyrants or Isareth the Awakener. Drill Bit is good with graveyard-matters cards. Thought Erasure can grab creatures too (unlike duress) and helps you search for combo pieces.
Removal:
Moment of Craving Gains you life, and is good vs aggro/small creatures. Nightmare's Thirst is good in the life gain version. Ixalan's Binding is a little better in the control version of this deck. Consecrate // Consume is good, gains you life, and can deal with graveyard effects. Vraska's Contempt deals with a lot and gains you life but is a tad expensive.
Counters
A more aggressive deck/lower land count decks will want to run Spell Pierce. Negate is better with more lands and vs control. Sinister Sabotage is good with other surveil cards like Thought Erasure, Discovery // Dispersal and Disinformation Campaign which is more of a controlling deck. Absorb is good in life-gain version of this deck and is probably good vs burn. Wizard's Retort is good in the wizard's version of this deck.
Card Draw/Selection:
Discovery // Dispersal Search for Azcanta // Azcanta, the Sunken Ruin and Teferi, Hero of Dominaria are all good in control. Dawn of Hope is good with life gain. Mystic Archaeologist is a wizard and is good both early and late.
What's left for this deck? It needs tuning for sure, and there are a lot of routes to go into. The best thing you can do is choose a theme and focus on that more than I currently am, but that comes down to your play-style and preferences.
The BW Lifegain version would probably focus more on Vampires, and I'll leave adapting someone else's list as an exercise to the reader (probably moving Sorcerer's Wand to the sideboard and bringing in On Serra's Wings. Remember that life-gain that doesn't do anything else isn't super useful, which is an important reason to leave out more "pure" life gain cards.