Grimgrin + Undead Alchemist + Phenax
Use Grimgrin to mill using Phenax-granted ability, any creatures that get milled create a new Zombie for Grimgrin to eat and untap, repeat

Exploit with Sidisi to get Rooftop Storm


Go infinite with these with Rooftop Storm:

Grimgrin + Gravecrawler
{B}: untap and add a +1/+1 counter to Grimgrin

Altar of Dementia + Gravecrawler
{B}: put the top two cards of target player's library into his or her graveyard

Blasting Station + Gravecrawler
{B}: Deal 1 damage to target creature or player

Diregraf Captain + Gravecrawler
{B}: Deal 1 damage to target opponent