Gravitational Shift

Creatures with flying get +2/+0.
Creatures without flying get -2/-0.

Magus of the Moat

Aven Mindcensor

Flash
Flying
If an opponent would search a library, that player searches the top four cards of that library instead.

Marble Diamond

Marble Diamond enters tapped.
{T}: Add {W}.

Watcher of the Spheres

Flying
Creature spells with flying you cast cost {1} less to cast.
Whenever another creature you control with flying enters, Watcher of the Spheres gets +1/+1 until end of turn.