Sleep

Tap all creatures target player controls. Those creatures don't untap during that player's next untap step.

Mana Leak

Counter target spell unless its controller pays {3}.

Scry 1. (Look at the top card of your library. You may put that card on the bottom.)
Draw a card.

Curious Obsession

Enchant creature
Enchanted creature gets +1/+1 and has "Whenever this creature deals combat damage to a player, you may draw a card."
At the beginning of your end step, if you didn't attack with a creature this turn, sacrifice this Aura.

Essence Scatter

Insectile Aberration

Delver of Secrets

At the beginning of your upkeep, look at the top card of your library. You may reveal that card. If an instant or sorcery card is revealed this way, transform this creature.

Delver of Secrets // Insectile Aberration

Faerie Miscreant

Flying
When this creature enters, if you control another creature named Faerie Miscreant, draw a card.

Island

Merfolk Trickster

Flash
When this creature enters, tap target creature an opponent controls. It loses all abilities until end of turn.