A 4/4 merfolk wizard that requires its controller to champion a merfolk, whenever this creature deals damage to a player, its controller can sacrifice a merfolk to take an extra turn after this one
A three power Commander saves multiple hits, but thats seven hits, which starts pushing the bounds of an individual threat being quick enough
do you want to do Ghoulraiser, Gravecrawler, Lord of the Undead, etc., or do you want to do Cemetery Reaper, Graveyard Marshal, Tymaret, etc
While it is a totally different game, the supercharger that the Terraforming Mars expansion Prelude offers gets that game up and running faster, without a hit to the gameplay