Appa, Steadfast Guardian (Borderless): Avatar: The Last Airbender Standard then you may cast any

then you may cast any number of spells from among those cards without paying their mana costs

You may put a nonwhite creature card from your hand onto the battlefield

Traitor to Mortals enters the battlefield with X +1/+1 counters on it

Whenever a source an opponent controls deals damage to you

Orcish Bowmasters deals 1 damage to any target

Appa, Steadfast Guardian (Borderless): Avatar: The Last Airbender Standard then you may cast anyFlash Flying When Appa enters, airbend any number of other target nonland permanents you control. (Exile them. While each one is exiled, its owner may cast it for {2} rather than its mana cost.) Whenever you cast a spell from exile, create a 1 1 white Ally creature token.