Library of Leng

You have no maximum hand size.
If an effect causes you to discard a card, discard it, but you may put it on top of your library instead of into your graveyard.

Mystic Snake

Flash
When this creature enters, counter target spell.

Cognivore

Flying
Cognivore's power and toughness are each equal to the number of instant cards in all graveyards.

Megrim

Whenever an opponent discards a card, this enchantment deals 2 damage to that player.

Aether Burst

Return up to X target creatures to their owners' hands, where X is one plus the number of cards named Aether Burst in all graveyards as you cast this spell.

Island

Golgari Guildgate

This land enters tapped.
{T}: Add {B} or {G}.

Forest

Capsize

Buyback {3} (You may pay an additional {3} as you cast this spell. If you do, put this card into your hand as it resolves.)
Return target permanent to its owner's hand.

Withdraw

Return target creature to its owner's hand. Then return another target creature to its owner's hand unless its controller pays {1}.

Repulse

Return target creature to its owner's hand.
Draw a card.

Boomerang

Return target permanent to its owner's hand.

Recoil

Return target permanent to its owner's hand. Then that player discards a card.

Yavimaya Coast

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

Simic Guildgate

This land enters tapped.
{T}: Add {G} or {U}.

Gaea's Skyfolk

Unsummon

Return target creature to its owner's hand.

Geth's Grimoire

Whenever an opponent discards a card, you may draw a card.

Warped Devotion

Whenever a permanent is returned to a player's hand, that player discards a card.