There will be superheroes, villains, equipment, and epic abilities brand new to Magic
It combos very well with cards like Splinter Twin, allowing you to get infinite extra combat steps
Technomancer is a very powerful Magic card, and if youre in a graveyard-based deck, youll be able to accrue serious value off of it
A strong zombie commander does one of three things: it makes tokens to go wide, it recurs creatures from the graveyard so your board never stays cleared, or it turns a pile of dying zombies into card advantage and life drain
Flashback will probably still be the most dominant way to take advantage of Sevinne, with a much greater saturation of cards with the mechanic (plus cards that favorably interact with flashback, like Burning Vengeance or Secrets of the Dead)
Whereas Index and Visions dont really accomplish much, Tahngarths Glare can actively hurt you