Its not overly difficult to untap and spend three mana during your first main phase after your opponents have dedicated all of their best creatures to swinging at other players, which means that Split Up is likely to be an instant classic of the board wipe genre
Whenever Demilich attacks, exile up to one target instant or sorcery card from your graveyard
Playing Around Mulcharmies Crystrons summon from all locations, but arent really extremely vulnerable to any specific Mulcharmy because they dont summon that much in any specific location
Two particularly powerful artifacts, the Powerstone and the Weakstone, accidentally summoned the extraplanar horrors called the Phyrexians, leading to an escalation in battle until Urza unleashed a mighty blast from another artifact, the Golgothian Stylex, that essentially acted as a nuke, apparently wiping out Mishra and the Phyrexians
I am also considering Mind Crush but maybe I'll leave that as side deck