Tasha, the Witch Queen - Battle for Baldur's Gate Promos

Whenever you cast a spell you don't own, create a 3/3 black Demon creature token.

[+1]: Draw a card. For each opponent, exile up to one target instant or sorcery card from that player's graveyard and put a page counter on it.

[−3]: You may cast a spell from among cards in exile with page counters on them without paying its mana cost.

Tasha, the Witch Queen can be your commander.