I'd just like to say it's surprising Liliana of the Veil is out of your price range, and yet you have 4 Cavern of Souls , ($25 a pop). but lili isn't great in the current standard anyways, but I think you can drop the Killing Wave in favor of Mutilate and replace Bone Splinters with Ultimate Price and if you want you sould see about adding card:Altar's Reap excellent spell against decks that run Pillar of Flame , sack your Gravecrawler in response to the pillar, and it's a part of the asting cost, so even if they counter it the sacrifice portion still goes through. Cackling Counterpart might be something to look into as well, if you have one or two Blood Artist out you can respond to a board wipe with counterpart, copying an artist to get extra damage in, and then still have the flashback available. P.S. sorry for the wall of text :3

@Rooah711 I got the Cavern of Souls pretty cheap, and i valued them higher than liliana at the time. Killing Wave is really nice in my opinion simply because you have different options with it, It's not just "destroy all creatures" It's more like "destroy the creatures you want to destroy, keep the wants you don't" but i might have to side some Mutilate s. The Bone Splinters will have to wait to be playtested with properly before i decide about that. The card:Altar's Reap thing is actually really nice, i never thought of playing it like that! I'll definitaly check that out! The Cackling Counterpart s however will be difficult because i almost never will be able to produce two blue mana consistently. :( P.S. Thanks for the wall of help! :)

Have you considered Essence Harvest ?

Yeah, i thought about it, if you mean using it with Grimgrin, Corpse-Born . It could work! But since i still haven't received my deck (thanks coolstuffinc) i haven't had time to playtest. But i will when it shows up! Thanks!

Oh, one thing I forgot to mention, Endless Ranks of the Dead is great with Grimgrin, Corpse-Born , used it in a B/U zombie mill deck and it generates an insane amount of grimgrin fodder.