Reclamation Sage

When Reclamation Sage enters, you may destroy target artifact or enchantment.

Acidic Slime

Deathtouch (Any amount of damage this deals to a creature is enough to destroy it.)
When Acidic Slime enters, destroy target artifact, enchantment, or land.

Coiling Oracle

When Coiling Oracle enters, reveal the top card of your library. If it's a land card, put it onto the battlefield. Otherwise, put that card into your hand.

Sakura-Tribe Elder

Sacrifice Sakura-Tribe Elder: Search your library for a basic land card, put that card onto the battlefield tapped, then shuffle.

Momir Vig, Simic Visionary

Whenever you cast a green creature spell, you may search your library for a creature card, reveal it, then shuffle and put that card on top.
Whenever you cast a blue creature spell, reveal the top card of your library. If it's a creature card, put that card into your hand.

Eternal Witness

When Eternal Witness enters, you may return target card from your graveyard to your hand.

Frilled Mystic

Flash
When Frilled Mystic enters, you may counter target spell.

Jungle Barrier

Defender (This creature can't attack.)
When Jungle Barrier enters, draw a card.