Tempest Hawk

Flying
Whenever this creature deals combat damage to a player, you may search your library for a card named Tempest Hawk, reveal it, put it into your hand, then shuffle.
A deck can have any number of cards named Tempest Hawk.

Hare Apparent

When this creature enters, create a number of 1/1 white Rabbit creature tokens equal to the number of other creatures you control named Hare Apparent.
A deck can have any number of cards named Hare Apparent.

Elesh Norn, Grand Cenobite

Vigilance
Other creatures you control get +2/+2.
Creatures your opponents control get -2/-2.

Elesh Norn, Mother of Machines

Vigilance
If a permanent entering causes a triggered ability of a permanent you control to trigger, that ability triggers an additional time.
Permanents entering don't cause abilities of permanents your opponents control to trigger.

Witty Roastmaster

Alliance — Whenever another creature you control enters, this creature deals 1 damage to each opponent.

Kudo, King Among Bears

Other creatures have base power and toughness 2/2 and are Bears in addition to their other types.

Duskana, the Rage Mother

When Duskana enters, draw a card for each creature you control with base power and toughness 2/2.
Whenever a creature you control with base power and toughness 2/2 attacks, it gets +3/+3 until end of turn.