Ricochet Trap

If an opponent cast a blue spell this turn, you may pay {R} rather than pay this spell's mana cost.
Change the target of target spell with a single target.

Archive Trap

If an opponent searched their library this turn, you may pay {0} rather than pay this spell's mana cost.
Target opponent mills thirteen cards.

Kobolds of Kher Keep

Devouring Hellion

As Devouring Hellion enters, you may sacrifice any number of creatures and/or planeswalkers. If you do, it enters with twice that many +1/+1 counters on it.

Field of Dreams

Players play with the top card of their libraries revealed.

Permafrost Trap

If an opponent had a green creature enter the battlefield under their control this turn, you may pay {U} rather than pay this spell's mana cost.
Tap up to two target creatures. Those creatures don't untap during their controller's next untap step.

Arrow Volley Trap

If four or more creatures are attacking, you may pay {1}{W} rather than pay this spell's mana cost.
Arrow Volley Trap deals 5 damage divided as you choose among any number of target attacking creatures.

Mindbreak Trap

If an opponent cast three or more spells this turn, you may pay {0} rather than pay this spell's mana cost.
Exile any number of target spells.

Dissipation Field

Whenever a permanent deals damage to you, return it to its owner's hand.

Crimson Kobolds

Rograkh, Son of Rohgahh

First strike, menace, trample
Partner (You can have two commanders if both have partner.)

Electrostatic Field

Defender
Whenever you cast an instant or sorcery spell, Electrostatic Field deals 1 damage to each opponent.

Dargo, the Shipwrecker

As an additional cost to cast this spell, you may sacrifice any number of artifacts and/or creatures. This spell costs {2} less to cast for each permanent sacrificed this way and {2} less to cast for each other artifact or creature you've sacrificed this turn.
Trample
Partner (You can have two commanders if both have partner.)

Lethargy Trap

If three or more creatures are attacking, you may pay {U} rather than pay this spell's mana cost.
Attacking creatures get -3/-0 until end of turn.

Inferno Trap

If you've been dealt damage by two or more creatures this turn, you may pay {R} rather than pay this spell's mana cost.
Inferno Trap deals 4 damage to target creature.

Edgin, Larcenous Lutenist

Each nonland card in your hand without foretell has foretell. Its foretell cost is equal to its mana cost reduced by {2}. (During your turn, you may pay {2} and exile it from your hand face down. Cast it on a later turn for its foretell cost.)
Whenever you cast your second spell each turn, goad target creature an opponent controls.

Memnite

Refraction Trap

If an opponent cast a red instant or sorcery spell this turn, you may pay {W} rather than pay this spell's mana cost.
Prevent the next 3 damage that a source of your choice would deal to you and/or permanents you control this turn. If damage is prevented this way, Refraction Trap deals that much damage to any target.

Ornithopter

Pitfall Trap

If exactly one creature is attacking, you may pay {W} rather than pay this spell's mana cost.
Destroy target attacking creature without flying.

Runeflare Trap

If an opponent drew three or more cards this turn, you may pay {R} rather than pay this spell's mana cost.
Runeflare Trap deals damage to target player equal to the number of cards in that player's hand.

Stone Idol Trap

This spell costs {1} less to cast for each attacking creature.
Create a 6/12 colorless Construct artifact creature token with trample. Exile it at the beginning of your next end step.

Crookshank Kobolds

Preyseizer Dragon

Flying
Devour 2 (As this enters, you may sacrifice any number of creatures. This creature enters with twice that many +1/+1 counters on it.)
Whenever Preyseizer Dragon attacks, it deals damage to any target equal to the number of +1/+1 counters on Preyseizer Dragon.

Predator Dragon

Flying, haste
Devour 2 (As this enters, you may sacrifice any number of creatures. This creature enters with twice that many +1/+1 counters on it.)

Whiplash Trap

If an opponent had two or more creatures enter the battlefield under their control this turn, you may pay {U} rather than pay this spell's mana cost.
Return two target creatures to their owners' hands.

Phyrexian Walker

Mystic Reflection

Choose target nonlegendary creature. The next time one or more creatures or planeswalkers enter this turn, they enter as copies of the chosen creature.
Foretell {U} (During your turn, you may pay {2} and exile this card from your hand face down. Cast it on a later turn for its foretell cost.)

Lavaball Trap

If an opponent had two or more lands enter the battlefield under their control this turn, you may pay {3}{R}{R} rather than pay this spell's mana cost.
Destroy two target lands. Lavaball Trap deals 4 damage to each creature.

Shield Sphere

Defender
Whenever Shield Sphere blocks, put a -0/-1 counter on it.

Thunder-Thrash Elder

Devour 3 (As this enters, you may sacrifice any number of creatures. This creature enters with three times that many +1/+1 counters on it.)

Space Beleren

Space sculptor (Space Beleren divides the battlefield into alpha, beta, and gamma sectors. If a creature isn't assigned to a sector, its controller assigns it to one. Opponents assign first.)
+1: Creatures in each sector can be blocked this turn only by creatures in the same sector.
−1: Put a +1/+1 counter on each creature in the sector of your choice.
−5: Destroy all creatures in the sector of your choice.

Delayed Blast Fireball

Delayed Blast Fireball deals 2 damage to each opponent and each creature they control. If this spell was cast from exile, it deals 5 damage to each opponent and each creature they control instead.
Foretell {4}{R}{R} (During your turn, you may pay {2} and exile this card from your hand face down. Cast it on a later turn for its foretell cost.)