Unsummon

Return target creature to its owner's hand.

Frost Lynx

When Frost Lynx enters, tap target creature an opponent controls. That creature doesn't untap during its controller's next untap step.

Riddlemaster Sphinx

Flying (This creature can't be blocked except by creatures with flying or reach.)
When Riddlemaster Sphinx enters, you may return target creature an opponent controls to its owner's hand.

Fortress Crab

Moat Piranhas

Merfolk Looter

Air Elemental

Befuddle

Target creature gets -4/-0 until end of turn.
Draw a card.

Sleep Paralysis

Enchant creature
When Sleep Paralysis enters, tap enchanted creature.
Enchanted creature doesn't untap during its controller's untap step.

Cloudkin Seer

Flying
When Cloudkin Seer enters, draw a card.

Divination

Captivating Gyre

Return up to three target creatures to their owners' hands.

Snapping Drake

Flying (This creature can't be blocked except by creatures with flying or reach.)

Inundate

Return all nonblue creatures to their owners' hands.

Octoprophet

When Octoprophet enters, scry 2. (Look at the top two cards of your library, then put any number of them on the bottom and the rest on top in any order.)