Haste
Celebration — Whenever Ash attacks, if two or more nonland permanents entered the battlefield under your control this turn, put a +1/+1 counter on Ash.
"Get up and dance! Let your feet thunder like forgehammers!"
(01/09/2023)
The permanents that entered the battlefield don't need to remain on the battlefield or under your control. Celebration abilities are checking for past events, not the current game state.
(01/09/2023)
Others are static abilities that give creatures abilities or power and toughness increases as long as two or more nonland permanents entered the battlefield under your control that turn.
(01/09/2023)
Celebration abilities only care if two or more nonland permanents entered the battlefield under your control in a turn. They won't get more powerful if more than two permanents entered the battlefield under your control in a turn.
(01/09/2023)
Some celebration abilities trigger at specific parts of the turn and check whether two or more nonland permanents entered the battlefield under your control already in that turn.
(01/09/2023)
Each celebration ability has a different effect.