Circular Logic

Counter target spell unless its controller pays {1} for each card in your graveyard.
Madness {U} (If you discard this card, discard it into exile. When you do, cast it for its madness cost or put it into your graveyard.)

Fire

Fire deals 2 damage divided as you choose among one or two targets.

Fire // Ice

Opposition

Tap an untapped creature you control: Tap target artifact, creature, or land.

Merfolk Looter

Flametongue Kavu

When this creature enters, it deals 4 damage to target creature.

Squirrel Nest

Enchant land
Enchanted land has "{T}: Create a 1/1 green Squirrel creature token."

Phantom Centaur

Protection from black
This creature enters with three +1/+1 counters on it.
If damage would be dealt to this creature, prevent that damage. Remove a +1/+1 counter from this creature.

Birds of Paradise

Island

Ray of Revelation

Destroy target enchantment.
Flashback {G} (You may cast this card from your graveyard for its flashback cost. Then exile it.)

Yavimaya Coast

{T}: Add {C}.
{T}: Add {G} or {U}. This land deals 1 damage to you.

Llanowar Elves

Roar of the Wurm

Create a 6/6 green Wurm creature token.
Flashback {3}{G} (You may cast this card from your graveyard for its flashback cost. Then exile it.)

Quiet Speculation

Search target player's library for up to three cards with flashback and put them into that player's graveyard. Then the player shuffles.

Shivan Reef

{T}: Add {C}.
{T}: Add {U} or {R}. This land deals 1 damage to you.

Simoon

Simoon deals 1 damage to each creature target opponent controls.

Forest

Karplusan Forest

{T}: Add {C}.
{T}: Add {R} or {G}. This land deals 1 damage to you.

Deep Analysis

Target player draws two cards.
Flashback—{1}{U}, Pay 3 life. (You may cast this card from your graveyard for its flashback cost. Then exile it.)

Wild Mongrel

Discard a card: This creature gets +1/+1 and becomes the color of your choice until end of turn.