Moonshaker Cavalry

Flying
When Moonshaker Cavalry enters, creatures you control gain flying and get +X/+X until end of turn, where X is the number of creatures you control.

Sol Ring

Bladegriff Prototype

Flying
Whenever Bladegriff Prototype deals combat damage to a player, destroy target nonland permanent of that player's choice that one of your opponents controls.

Mirror Entity

Changeling (This card is every creature type.)
{X}: Until end of turn, creatures you control have base power and toughness X/X and gain all creature types.

Mistmoon Griffin

Flying
When Mistmoon Griffin dies, exile Mistmoon Griffin, then return the top creature card of your graveyard to the battlefield.

Skystreamer

Assist (Another player can pay up to {4} of this spell's cost.)
Flying
When Skystreamer enters, target player gains 4 life.

Cathars' Crusade

Whenever a creature you control enters, put a +1/+1 counter on each creature you control.

Unyaro Griffin

Flying
Sacrifice Unyaro Griffin: Counter target red instant or sorcery spell.

Zuberi, Golden Feather

Flying
Other Griffin creatures get +1/+1.

Bloodline Pretender

Changeling (This card is every creature type.)
As Bloodline Pretender enters, choose a creature type.
Whenever another creature you control of the chosen type enters, put a +1/+1 counter on Bloodline Pretender.

Pearl Medallion

White spells you cast cost {1} less to cast.

Zeriam, Golden Wind

Flying
Whenever a Griffin you control deals combat damage to a player, create a 2/2 white Griffin creature token with flying.

Welcoming Vampire

Flying
Whenever one or more other creatures you control with power 2 or less enter, draw a card. This ability triggers only once each turn.