Wild Mongrel

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

Basking Rootwalla

{1}{G}: This creature gets +2/+2 until end of turn. Activate only once each turn.
Madness {0} (If you discard this card, discard it into exile. When you do, cast it for its madness cost or put it into your graveyard.)

Compost

Whenever a black card is put into an opponent's graveyard from anywhere, you may draw a card.

Arrogant Wurm

Trample
Madness {2}{G} (If you discard this card, discard it into exile. When you do, cast it for its madness cost or put it into your graveyard.)

Aquamoeba

Discard a card: Switch this creature's power and toughness until end of turn.

Waterfront Bouncer

{U}, {T}, Discard a card: Return target creature to its owner's hand.

Hydroblast

Choose one —
• Counter target spell if it's red.
• Destroy target permanent if it's red.

Tranquil Domain

Frantic Search

Draw two cards, then discard two cards. Untap up to three lands.

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.)

Forest

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.)

Gush

You may return two Islands you control to their owner's hand rather than pay this spell's mana cost.
Draw two cards.

Wonder

Flying
As long as this card is in your graveyard and you control an Island, creatures you control have flying.

Careful Study

Daze

You may return an Island you control to its owner's hand rather than pay this spell's mana cost.
Counter target spell unless its controller pays {1}.

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.)