Commander has been a favored format of mine for a while. I ran a
Grimgrin, Corpse-born for a while before Theaximunsar and Nekusar pilfered the blue black Commander seat from him. That being said, Innistrad flavored cards include the first two I mentioned before,
Havengul Runebinder and
Relentless Dead (can a zombie deck really avoid a good spot for
Relentless Dead?) One would let you use
dead cards to boost your swarm, the other would give you an
abundance of graveyard recursion. Also in the realm:
Tragic Slip. Great way to kill off big threats quickly. Even if opponent cycles the graveyard, he will eventually run afoul of the
Undead Alchemist you already have in deck to mill exiling him into 2/2 zombie tokens for you.