Stonecloaker has a ton of uses, that I feel it can be a strong addition to just about any cube that has the right cards. Obviously you want stuff with ETB abilities, which there are a ton of (and of course with the 'derms. Classic). Even in a white weenie deck it's solid just for dodging removal.
Loaming Shaman is kind of questionable though. I guess the thought is that you can rebuy your bombs that you're already used. If you want another graveyard hater, he's has enough general utility that he is your 4th option.
It's pretty easy to beat the Scarab just on the board though. Play a bigger creature and be on the defensive while you stabilize and get ahead. Obviously you don't want to try to attrition the scarab out. Targeting it with Flametongue Kavu sounds like a terrible idea. Not to mention, white can just exile/pacify it.
Granted, some decks Scarab will just be good again. You obviously can't fight it with counters or creature destruction. It's good to have cards that are good/weak against various archetypes.
The crusaders are way overpowered. The lifelink will easily replace whatever you pay to cast them on turn 1, and an aggro deck really wouldn't care. Any aggressive deck could basically run 4 of each and not even think twice.
As for the other ones, I think you're digging a little deep into the design space. That's fine design experimentation, but I think there's better, much more shallow, design space to be mined with phyrexian mana.
I don't like the pump spell. It's too simple for the crazy casing around it. It would also probably be too good of a Hatred.
The blue card looks nifty, but honestly I think it would play terribly. It's just an expensive draw spell, and it gives you an extra reason to not pay life. Phybrid cards should make you tempted to pay life to play them, that's why all existing phybrid cards are colorless outside of their phyrexian mana.
Spelljack is a fun mechanic to think about, and is the type of things designers often go to. However, it is a terrible mechanic to play and would not appeal to most players. It is entirely a drawback mechanic, and creates complicated situations. Also, I don't see it going in common.
Unravel is a fine idea, but is rather dangerous with graveyard matters cards. Honestly, I think Ripple is a better implementation of what you are trying to do.
As for the cards you posted, I don't really see a mechanical tie between them. Try to resist just throwing card designs you like together. Also, work exclusively with commons until you know what your set is going to look like.
The first card is pretty dangerous. I made a card like this (that made all spells cost 2 more, on a 6 drop 5/5 flier) and it was pretty good when I tested it out. Yours has a less impressive size, but the ability can be much more annoying. I think it's too much.
The second one is fun, kind of like Radha. People would probably enjoy it, and it's not too powerful, making it a good johnny card.
The third one is a nice reanimator/show and tell hoser, but it should be a 3 mana 3/3 or a 2 mana 2/2. Being 4 mana really limits it's usefulness.
I think they can. The only aspect of protection that would be relevant is no targeting though, which really just stops countering.
It's pretty narrow, and would be better suited to just say "target spell can't be countered". Of course, if there's one implementation that makes sense, that would probably be it.
For the bonus card? It's kind of interesting. I don't think it should be a hybrid card. A 1UR draw 3 would be good. It should be a sorcery, though.
The baseline for peasant cube is extremely different from pauper cube. There are numerous incredibly powerful uncommons in the game that really increase the threshold of how good a card has to be to make it.
That said, there is still a void at high-curve bombs. Death by Dragons is a somewhat lackluster 5/5 flier for 6, but red doesn't have one of those yet. Personally both dragons probably make the cut, but I don't know for certain without having a peasant cube built.
As for other cards that look sweet: Azure Mage seems solid. It takes a lot of mana, but it's still a 2/1 for 2 in blue.
Phantasmal Dragon is a slam dunk. It's a fairly high-powered format, and there won't be many throw-away cards that you can pitch at it. Meanwhile you get a 5/5 flier for 4.
Vampire Outcasts is probably decent. 4/4 lifelinkers are pretty big, even though times you need to gain life, and times you activate bloodthirst aren't that closely related. You have tons of sweet value cards like Skinrender in this slot, but I'm having another Scourge of Numai sized beater is probably pretty nice for the aggressive decks.
Bloodstorm Berserker is probably pretty good. 3/3s for 2 mana are nice, and there are more awesome 1 drops that you can fill your aggro deck with to trigger bloodthirst. It's also hard to block.
Hunter's Insight draws cards in green. It's dangerous, but the upside is staggering.
Stingwebbing Spider seems pretty sweet. There are some really good fliers at uncommon, and this will tear them up.
Web is great against utility creatures, such at tappers (which green has a tough time with). Also, it can lock down an evasive creature, giving green time to win with superior green creatures.
The Giant Growth comparison for frost breath is pretty weak imo. Growth is a much weaker card than Blinding Beam, and is much more narrow. Personally I think Frost Breath will have offensive applications for breaking stalemates, but I think it's a good enough defensive spell to warrant an inclusion. Because, honestly, beam was always a better defensive card than an offensive card. That's why it's better than Sleep ever was.
I find Glasskite to be at it's best in removal heavy decks that are kind of light on creatures. In such a case, Fleetwing's 2 toughness won't really matter.
Frost Breath obviously isn't a superb blue card, and comparing it to something like Undo is kind of unfair. Still, I think it's a solid defensive card. I like to have diverse spell effects in my cube (if I just put the best ones, my black would be half removal), and Frost Breath is probably better than Choking Tethers, which I run and which has done good things for me in the past.
Blinding Beam is obviously better just because it is white, and has more impact offensively. That said, I've cast plenty of defensive Blinding Beams. A large reason I'm excited about it is because I enjoy beam so much, and I understand if other people think it's not quite up to snuff.
As for Bangchuckers vs Archaeologist, obviously the Archaeologist is better, as it's cheaper, untaps, and kills a wider variety of stuff. Still, the point was that just because a card can do nothing, it can still be good if the upside is large enough. Pinging for 2 is pretty sweet, and the power level of core set limited tends to be a bit lower, so expect to see some dynamite in the near future.
Frost Breath is a cube now for me. It's enough of a Blinding Beam, and beam is an awesome card. It's better than sleep, as it is an instant.
Aven Fleetwing is more on the level of Shimmering Glasskite. It has one less power than the return to library guys, but it doesn't set you back a card and it doesn't require mana. I expect it to be spectacular.
Pride Guardian imo isn't good enough. It doesn't really mesh with the white color identity. Also, there isn't much top end to be worth stalling to get to, especially not in white.
Goblin Bangchuckers is uncommon. For actually limited play, I think it's good. It's reminiscent of Goblin Archaeologist, which was a top pick in mirrodin limited.
Goblin Fireslinger is a card I kind of like. Sticking it on turn 1 and curving out is kind of insane. They will have to spend a removal spell of some sort on it at some point.
Arachus Web is obviously awesome. Most creatures don't have 4
power anyways!
Armored Warhorse is a "new" vanilla benchmark, but white two drops are already pretty amazing.
Peregrine Griffin is pretty lulzy. I don't think the first strike is very relevant, making it a more expensive Makindi Griffin, which people don't run.
Stave Off is actually nice and cheap. It's no shelter, but white could use a few more spell effects. It may have a shot in some lists. I'll stick to Dawn Charm though.
Saw someone play Rock Slide in LSV's latest draft video. The card seems solid, and is pretty mana efficient. I'm going to try it out in my next cube update.
Power Sink is definitely better than Syncopate. There isn't that much that really cares about being in the graveyard. Personally, I'd rather have Broken Ambitions just for the small amount of card filtering.
Logic Knot however I have been using, and it's pretty solid. There isn't much else that uses the same resource as delve, so very often it's just free. Early game you gotta get some stuff there, but even on turn 3 you can probably get there with the Spell Snip effect. The reason it is good is that you can play a threat and leave 2 mana up, and still be able to counter whatever they have. It's one of the lower tier counters, but it's definitely one to try out if you want another counter.
For Impulse, I'm under the impression it was just printed incorrectly (the wording on the card makes no sense, why put the cards on the bottom if you're shuffling?). It's been errata'd for a very long time. As for the card itself, I'm of the opinion that it is rather lackluster. It was a great constructed card back in the day because in most formats, card quality varies heavily amongst a single deck (you need to find a combo piece, for instance). In Commons Cube, the card quality is rather stable, which makes these types of draw spells somewhat lackluster. Impulse is worse than Preordain in that you have to bottom 3. If you see four sweet cards, you just shot yourself in the foot.
As for the 2012 cards, Lawkeeper is obviously great, though there's such a huge glut of tappers that he's merely a small upgrade.
The bear is kind of weird in that there usually aren't many targeting effects that aren't premium removal. However, his size kind of makes that pointless. He gets invalidated rapidly in combat, and only has a reason to exist if you can be super-aggressive. In blue, that doesn't seem to be likely, and any blue aggressive deck is probably trying to do it with fliers, while clogging up the ground.
The bat actually kind of tempts me. Bloodthirst is a pretty easy mechanic to trigger, but on turn 2, not so much. If there's one color that can do it, it's black though. Turn 2 Lacerator/Carnophage into turn 2 bat is solid. There's a lot of good black 2 drops, but I think he's close in power level to Fledgling Djinn.
The most anticipated card for me from 2012 is going to be the Giant Growth replacement. It seems very likely that it will be a Vines of Vastwood type card, given that hexproof is a brand new keyworded mechanic.
For Smallpox, basically you want to maximize the discard and the creature aspect of it. For creature, play it in a deck that has either creatures you don't want later on, or a creature-light deck.
To maximize the discard, run the card with more discard effects. Discard effects are excellent in multiples, as they let you get past the initial "I can afford to discard a land". Following Smallpox up with, say, Hymn, can be a huge beating.
And of course Flagstones of Troikair is good for the land part, but that card doesn't really cut it in cube.
Loaming Shaman is kind of questionable though. I guess the thought is that you can rebuy your bombs that you're already used. If you want another graveyard hater, he's has enough general utility that he is your 4th option.
It's pretty easy to beat the Scarab just on the board though. Play a bigger creature and be on the defensive while you stabilize and get ahead. Obviously you don't want to try to attrition the scarab out. Targeting it with Flametongue Kavu sounds like a terrible idea. Not to mention, white can just exile/pacify it.
Granted, some decks Scarab will just be good again. You obviously can't fight it with counters or creature destruction. It's good to have cards that are good/weak against various archetypes.
As for the other ones, I think you're digging a little deep into the design space. That's fine design experimentation, but I think there's better, much more shallow, design space to be mined with phyrexian mana.
I don't like the pump spell. It's too simple for the crazy casing around it. It would also probably be too good of a Hatred.
The blue card looks nifty, but honestly I think it would play terribly. It's just an expensive draw spell, and it gives you an extra reason to not pay life. Phybrid cards should make you tempted to pay life to play them, that's why all existing phybrid cards are colorless outside of their phyrexian mana.
Spelljack is a fun mechanic to think about, and is the type of things designers often go to. However, it is a terrible mechanic to play and would not appeal to most players. It is entirely a drawback mechanic, and creates complicated situations. Also, I don't see it going in common.
Unravel is a fine idea, but is rather dangerous with graveyard matters cards. Honestly, I think Ripple is a better implementation of what you are trying to do.
As for the cards you posted, I don't really see a mechanical tie between them. Try to resist just throwing card designs you like together. Also, work exclusively with commons until you know what your set is going to look like.
The second one is fun, kind of like Radha. People would probably enjoy it, and it's not too powerful, making it a good johnny card.
The third one is a nice reanimator/show and tell hoser, but it should be a 3 mana 3/3 or a 2 mana 2/2. Being 4 mana really limits it's usefulness.
It's pretty narrow, and would be better suited to just say "target spell can't be countered". Of course, if there's one implementation that makes sense, that would probably be it.
For the bonus card? It's kind of interesting. I don't think it should be a hybrid card. A 1UR draw 3 would be good. It should be a sorcery, though.
That said, there is still a void at high-curve bombs. Death by Dragons is a somewhat lackluster 5/5 flier for 6, but red doesn't have one of those yet. Personally both dragons probably make the cut, but I don't know for certain without having a peasant cube built.
As for other cards that look sweet:
Azure Mage seems solid. It takes a lot of mana, but it's still a 2/1 for 2 in blue.
Phantasmal Dragon is a slam dunk. It's a fairly high-powered format, and there won't be many throw-away cards that you can pitch at it. Meanwhile you get a 5/5 flier for 4.
Vampire Outcasts is probably decent. 4/4 lifelinkers are pretty big, even though times you need to gain life, and times you activate bloodthirst aren't that closely related. You have tons of sweet value cards like Skinrender in this slot, but I'm having another Scourge of Numai sized beater is probably pretty nice for the aggressive decks.
Bloodstorm Berserker is probably pretty good. 3/3s for 2 mana are nice, and there are more awesome 1 drops that you can fill your aggro deck with to trigger bloodthirst. It's also hard to block.
Hunter's Insight draws cards in green. It's dangerous, but the upside is staggering.
Stingwebbing Spider seems pretty sweet. There are some really good fliers at uncommon, and this will tear them up.
The Giant Growth comparison for frost breath is pretty weak imo. Growth is a much weaker card than Blinding Beam, and is much more narrow. Personally I think Frost Breath will have offensive applications for breaking stalemates, but I think it's a good enough defensive spell to warrant an inclusion. Because, honestly, beam was always a better defensive card than an offensive card. That's why it's better than Sleep ever was.
Frost Breath obviously isn't a superb blue card, and comparing it to something like Undo is kind of unfair. Still, I think it's a solid defensive card. I like to have diverse spell effects in my cube (if I just put the best ones, my black would be half removal), and Frost Breath is probably better than Choking Tethers, which I run and which has done good things for me in the past.
Blinding Beam is obviously better just because it is white, and has more impact offensively. That said, I've cast plenty of defensive Blinding Beams. A large reason I'm excited about it is because I enjoy beam so much, and I understand if other people think it's not quite up to snuff.
As for Bangchuckers vs Archaeologist, obviously the Archaeologist is better, as it's cheaper, untaps, and kills a wider variety of stuff. Still, the point was that just because a card can do nothing, it can still be good if the upside is large enough. Pinging for 2 is pretty sweet, and the power level of core set limited tends to be a bit lower, so expect to see some dynamite in the near future.
Aven Fleetwing is more on the level of Shimmering Glasskite. It has one less power than the return to library guys, but it doesn't set you back a card and it doesn't require mana. I expect it to be spectacular.
Skywinder Drake is a card I'll add in. I love my Cloud Spirits, and they get better in multiples.
Pride Guardian imo isn't good enough. It doesn't really mesh with the white color identity. Also, there isn't much top end to be worth stalling to get to, especially not in white.
Goblin Bangchuckers is uncommon. For actually limited play, I think it's good. It's reminiscent of Goblin Archaeologist, which was a top pick in mirrodin limited.
Goblin Fireslinger is a card I kind of like. Sticking it on turn 1 and curving out is kind of insane. They will have to spend a removal spell of some sort on it at some point.
Arachus Web is obviously awesome. Most creatures don't have 4
power anyways!
Vampire Outcasts is uncommon unfortunately (otherwise it would be sweet).
I am excited about Gorehorn Minotaur, but that's it so far =[
Titanic Growth is pretty mediocre. It's probably worse than Giant Growth was.
Savage Silhouette functional reprint. Perhaps someone wants it, but I've already cut sihouette myself.
Sorin's Thirst is a solid card, but there's so many good black 2 mana removal spells that won't make the cut.
Devouring Swarm looks usable, if unexciting (certainly no Liliana's Specter)
Armored Warhorse is a "new" vanilla benchmark, but white two drops are already pretty amazing.
Peregrine Griffin is pretty lulzy. I don't think the first strike is very relevant, making it a more expensive Makindi Griffin, which people don't run.
Stave Off is actually nice and cheap. It's no shelter, but white could use a few more spell effects. It may have a shot in some lists. I'll stick to Dawn Charm though.
Logic Knot however I have been using, and it's pretty solid. There isn't much else that uses the same resource as delve, so very often it's just free. Early game you gotta get some stuff there, but even on turn 3 you can probably get there with the Spell Snip effect. The reason it is good is that you can play a threat and leave 2 mana up, and still be able to counter whatever they have. It's one of the lower tier counters, but it's definitely one to try out if you want another counter.
For Impulse, I'm under the impression it was just printed incorrectly (the wording on the card makes no sense, why put the cards on the bottom if you're shuffling?). It's been errata'd for a very long time. As for the card itself, I'm of the opinion that it is rather lackluster. It was a great constructed card back in the day because in most formats, card quality varies heavily amongst a single deck (you need to find a combo piece, for instance). In Commons Cube, the card quality is rather stable, which makes these types of draw spells somewhat lackluster. Impulse is worse than Preordain in that you have to bottom 3. If you see four sweet cards, you just shot yourself in the foot.
As for the 2012 cards, Lawkeeper is obviously great, though there's such a huge glut of tappers that he's merely a small upgrade.
The bear is kind of weird in that there usually aren't many targeting effects that aren't premium removal. However, his size kind of makes that pointless. He gets invalidated rapidly in combat, and only has a reason to exist if you can be super-aggressive. In blue, that doesn't seem to be likely, and any blue aggressive deck is probably trying to do it with fliers, while clogging up the ground.
The soul has a terrible clock. I don't think you'd run Prickly Boggart or Nightshade Stinger in your cube. He isn't much better. (try Pulse Tracker instead)
The bat actually kind of tempts me. Bloodthirst is a pretty easy mechanic to trigger, but on turn 2, not so much. If there's one color that can do it, it's black though. Turn 2 Lacerator/Carnophage into turn 2 bat is solid. There's a lot of good black 2 drops, but I think he's close in power level to Fledgling Djinn.
The most anticipated card for me from 2012 is going to be the Giant Growth replacement. It seems very likely that it will be a Vines of Vastwood type card, given that hexproof is a brand new keyworded mechanic.
To maximize the discard, run the card with more discard effects. Discard effects are excellent in multiples, as they let you get past the initial "I can afford to discard a land". Following Smallpox up with, say, Hymn, can be a huge beating.
And of course Flagstones of Troikair is good for the land part, but that card doesn't really cut it in cube.