Self-mill is key here, so some Dredge.

Pharika’s Two-Colored Cards

I like the flavor of black-green, so there’s plenty of cards I’d like to use here.

[scryfall]Catacomb Sifter[/scryfall] is a very efficient creature. The scrying ability is very strong, especially with what I want to do with this deck.

[scryfall]Deadbridge Chant[/scryfall] gives continuous card advantage in a fun way. Also, if you get one of the delve cards I put into the cube (with Phenax), this can be very strong.

[scryfall]Drown in Filth[/scryfall] is both self-mill and fair removal. It can miss badly, but at least it mills.

[scryfall]Gift of the Deity[/scryfall] has an interesting effect in this deck, since its going to have plenty of deathtouch.

[scryfall]Grave-Shell Scarab[/scryfall] provides Dredge.

[scryfall]Lotleth Troll[/scryfall] is an interesting card that’s very hard to evaluate. Its pretty bad card disadvantage, but at the same time, getting those creatures into your graveyard can be good as well.

[scryfall]Necrogenesis[/scryfall] is an alternative payoff for self-mill if you can’t find Pharika.

[scryfall]Nyx Weaver[/scryfall] is good self-mill, but also can get you something from the graveyard.

[scryfall]Pharika’s Mender[/scryfall] is flavorful.

[scryfall]Rot Farm Skeleton[/scryfall] is continuous self-mill.

[scryfall]Spiderspawning[/scryfall] is very strong. Maybe too strong.

[scryfall]Varolz, the Scar-Striped[/scryfall] could be another payoff card.

This is kind of hard, actually, but I guess this:

Black

First, Deathtouch enables easy trading with quite a few creatures. You get benefit from those creatures anyhow.

[scryfall]Typhoid Rats[/scryfall] and [scryfall]Pharika’s Chosen[/scryfall] are easy choices. So is [scryfall]Graveblade Marauder[/scryfall], although it can be quite oppressive at times. [scryfall]Ukud Cobra[/scryfall] is somewhat unassuming, but very powerful. Lastly, one of the best creatures around: [scryfall]Vampire Nighthawk[/scryfall].

[scryfall]Harvester of Souls[/scryfall] is in the Deathtouch camp, but also gives you other benefits, so its in.

Also, a couple of Dredge cards: [scryfall]Necroplasm[/scryfall] can be very poor in this deck at times, but its an interesting card. [scryfall]Stinkweed Imp[/scryfall] doesn’t quite have Deathtouch, but almost, so its actually in two camps here.

Green

Here we want pretty much the same thing as above, so first cheap Deathtouchers like [scryfall]Ambush Viper[/scryfall], [scryfall]Deadly Recluse[/scryfall], [scryfall]Heir of the Wilds[/scryfall], [scryfall]Nightshade Peddler[/scryfall] and [scryfall]Sedge Scorpion[/scryfall]. Also [scryfall]Acidic Slime[/scryfall].

Green does have something more though. It can force confrontations through Fights. The best way to do this [scryfall]Setessan Tactics[/scryfall].

I also want [scryfall]Nemesis of Mortals[/scryfall] in the cube, because of how nicely it works with self-mill.

This leaves room for one Dredge-card: [scryfall]Golgari Grave-Troll[/scryfall] (assuming I can find one cheap enough).