Anyway, this is a solid blue removal spell that most decks will probably be happy to play at least one of
Both sides of Valki are excellent, with Valki being hand disruption useful in the early game to steal a powerful creature (with the potential to turn into it later), while Tibalt is a great end-game card, capable of removing multiple creatures and stealing cards from your opponents' libraries to cast yourself
It wouldnt even need to be a tribal deck for Cavern of Souls to be valuable
Oversold Cemetery, Phyrexian Reclamation, and a flipped Journey to Eternity provide a great Reanimation plan, while Eternal Witness and Den Protector can do a handy impression of the old Crush of Tentacles deck from a season ago, the bonus being that we also get to bounce our own Energy makers, too
Its possible to pitch it and activate it earlier, too