marioguy3: Marrow-Gnawer players love you. The life loss is mitigated by how large the opponent's graveyard, but a mess of 2/1s seems like a good enough payoff without being completely broken.
Legend: Clean design, but this should be uncommon. No other complaints.
slimytrout: This is a neat combination of mechanics. With one other spell, this is
Barter in Blood. I feel this will be cast more for Overload than for its normal cost in the decks that will want to play this, but having the option is nice.
kwanyeegor-ii: This made me laugh pretty hard when I first read it. Treasure production in blue is definitely a bleed though; this would make more sense in Izzet colors.
MonoRedMage: This gets out of hand really quickly. In any format where rituals or cheap red cantrips are available, it's very easy to just lethal the opponent with any one-mana burn spell. The rarity is correct, but I feel this would be better as an additive effect than a multiplicative one.
netn10: The flavor text made me laugh quite hard. I do like how you can target the same thing with the copies if you don't want to exile multiple things. This seems disgusting with any creature that produces mana when it enters.
Burning-Tree Emissary much?
Henlock: I'm not sure how useful this is at sorcery speed. As an instant, this would be a great way to deal opposing wraths, but at four mana with a mechanic that requires you to play multiple spells, this could be difficult to make it worth the effort.
Almost all the designs were worthy of a vote, but I can only vote for three. Very competitive round this time.
1) netn10
2) Legend
3) kwanyeegor-ii