Part IV of many...
Here come the 3 drops!
Ashnod's Altar - Ashnod's Altar is a endless sacrifice outlet. If I want to kill one of my creatures (say Reassembling Skeleton) I can do it without spending mana, and I even get 2 colorless mana back. This rescues any of my creatures from being stolen from me, or suffering an embarrassing exile due to Swords to Plowshares.
Buried Alive - tutors for 3 of the best, most easily resurrect-able critters in my deck.
Cadaver Imp - I wanted one Gravedigger-type creature in this deck, and Cadaver Imp also flies which helps a ton. You really never know how the battlefield is going to play out, and if you are the guy with the flyer, perhaps wearing a Loxodon Warhammer, you might be able to hold your ground.
Jar of Eyeballs - A brand new card I am trying out. If my creatures start dying left and right, Jar of Eyeballs turns into a pretty decent tutor. And even when things are pretty deadlocked, 2 eyeballs is still a Scry 2 effect, same as a Crystal Ball.
Jaya Ballard, Task Mage - This legendary "spellshaper" wrecks other cards left and right. You are always going to run into blue permanents, guaranteed. Guaranteed! Don't even worry about that part. And the few non-blue creatures you find you can still roast. As a last resort, you can use this card as an Inferno to wipe the board. I've used all 3 abilities, and plan to use all 3 many more.
Loxodon Warhammer - A "broken" hammer to strap to any of your disposable creatures who seem to sink back into the earth as fast as you can raise them. The life gain is huge, and almost unavoidable since whatever creature you are using also has trample.
Pawn of Ulamog - Gets me more advantage out of my creatures dying. People are always trying to kill the creatures. Pawn of Ulamog gives me both a chump blocker and more mana. In some sort of dream scenario where I have Pawn, Reassembling Skeleton and Ashnod's Altar out, every single black mana I spend counts as 2 creature kills and generates an additional 3 colorless mana.
Phyrexian Arena - I draw another card every turn. Which helps rebuild my hand after Malfegor comes down. Really drawing cards is always good.
Rockslide Elemental - This is a fairly new card to my deck, so I'm still undecided how well this will work. Either dies immediately, or get really big. Multiplayer games multiply the bonuses, since more killing is generally happening. And who knows one turn I could make this 40/40, equip the hammer and kill someone.
Skull of Orm - Brings enchantments out of my graveyard. Black has lots of awesome enchantments, and normally doesn't have any way to get them back again. With one simple artifact from The Dark, now you can!
Stronghold Rats - This card was added to my deck for pure fun factor. These Rats are completely unblockable, and they force discards around the table. They might die pretty fast, but if they get left on the table for a couple of turns I will be laughing all the way to the bank. Ideally, they would also be wearing Lightning Greaves.
Taurean Mauler - Again, gets pretty big in multiplayer games. Dies right away or does a whole lot of damage.
Wheel of Fortune - Dumps all my awesome cards in the graveyard, and gives me a fresh hand. Sometimes my hand is exactly zero, in which case I just get 7 new cards. Sets me up with reanimation targets in other people's graveyards.
So there are the 3 drops. I've noticed this bunch of cards is significantly more exciting than the previous more utility-minded 2 drops. From here on out, should be mostly crazy explosions and money falling out of the sky. Next up are the 4 casting-costers!