Brainstealer Dragon

Flying
At the beginning of your end step, exile the top card of each opponent's library. You may play those cards for as long as they remain exiled. If you cast a spell this way, you may spend mana as though it were mana of any color to cast it.
Whenever a nonland permanent an opponent owns enters the battlefield under your control, they lose life equal to its mana value.

Gruesome Deformity

Enchant creature
Enchanted creature has intimidate. (It can't be blocked except by artifact creatures and/or creatures that share a color with it.)

Bubbling Muck

Until end of turn, whenever a player taps a Swamp for mana, that player adds an additional {B}.

Etherium Pteramander

Flying
This creature can block only creatures with flying.
{6}{B}: Adapt 4. This ability costs {1} less to activate for each other artifact you control. (If this creature has no +1/+1 counters on it, put four +1/+1 counters on it.)

Callous Inspector

Menace (This creature can't be blocked except by two or more creatures.)
When this creature dies, it deals 1 damage to you. Create a Clue token. (It's an artifact with "{2}, Sacrifice this token: Draw a card.")

Banehound

Rev, Tithe Extractor

Whenever you attack, target creature gains deathtouch until end of turn.
Whenever one or more creatures you control deal combat damage to a player, create a Treasure token, then look at the top card of that player's library and exile it face down. You may cast that card for as long as it remains exiled. (A Treasure token is an artifact with "{T}, Sacrifice this token: Add one mana of any color.")

Swamp

Defile

Target creature gets -1/-1 until end of turn for each Swamp you control.

Blight Keeper

Flying
{7}{B}, {T}, Sacrifice this creature: Target opponent loses 4 life and you gain 4 life.

Changeling Outcast

Changeling (This card is every creature type.)
This creature can't block and can't be blocked.

Prickly Boggart

Fear (This creature can't be blocked except by artifact creatures and/or black creatures.)