1 Woe Strider
This will make the game fun and full of surprises
This already works well with the handful of zombie-synergies in Kaldheim (Narfi, Betrayer King, Draugr Necromancer, Draugr Recruiter, Priest of the Haunted Ridge), but even if you're not after opponents' braiiiiinsss, options abound
In addition to the obvious things like Syphon cards (do some effect to each other player, gain benefits depending on how many other players this hit), there are cards that affect a random opponent, cards that give everyone the game the ability to join forces to create a big effect (for example, a sorcery that lets everyone pitch in mana and then lets everyone put lands into play from their decks), and Enchant Creature cards sorry Auras that boost the creature while preventing it from attacking to
Whether you're sorting a Commander deck-builder's binder, a Standard collection by set, or a casual player's "stuff I might use someday" pile, the same 77 dividers cover it
If one player refuses to give up their creature, this is often followed by the others following suit