Ash, Party Crasher

Haste
Celebration — Whenever Ash, Party Crasher attacks, if two or more nonland permanents entered the battlefield under your control this turn, put a +1/+1 counter on Ash.

Stroke of Midnight

Destroy target nonland permanent. Its controller creates a 1/1 white Human creature token.

Bespoke Battlegarb

Equipped creature gets +2/+0.
Celebration — At the beginning of combat on your turn, if two or more nonland permanents entered the battlefield under your control this turn, attach Bespoke Battlegarb to up to one target creature you control.
Equip {2} ({2}: Attach to target creature you control. Equip only as a sorcery.)

Belligerent of the Ball

Celebration — At the beginning of combat on your turn, if two or more nonland permanents entered the battlefield under your control this turn, target creature you control gets +1/+0 and gains menace until end of turn. (It can't be blocked except by two or more creatures.)

Lady of Laughter

Flying
Celebration — At the beginning of your end step, if two or more nonland permanents entered the battlefield under your control this turn, draw a card.