If it weren't for the temples, you could almost call this swamp tribal.

This is the central card of the deck. Ideally, we can drop enough swamps on the board to drain the opponent's life for the victory. Many of our cards have neat interaction with Dread Presence.

Yarok doubles enter the battlefield (ETB) effects on just about everything. When a creature, say Ravenous Chupacabra, enters the battlefield, it essentially triggers its own text. Yarok would double that, meaning our one Chupacabra will destroy two enemy creatures.

For 4 mana, we drop a 4/4 body on the board as well as get another chance to proc some ETB's by bouncing our creatures back to hand. This card came up when I searched "yarok" in the deck builder interface, and I'd be a liar if I told you I didn't think, "it fits for flavour, why not?" Maybe there are better alternatives (Exclusion Mage?) and it will just have to take some testing to see what works.

Nissa in a mostly black deck may not seem like a great idea (we only have 4 Forests!), but her +1 loyalty ability makes some prime targets for the Wavecrasher. Animating a swamp to make it a creature, then bouncing the creature land (after using it to attack and/or tapping it to get some extra mana) gives us an opportunity to get another proc off our dread presence. You only need 3 or 4 different cards for this particular combo. Now that's efficiency!

Yarok also doubles the swampfall effect for Dread Presence, so every time you play a land (not including the 3 non-swamps) you could draw 2 cards, gain 4 life, or even do one of each.

All you need is a dread presence, a Yarok, two green mana sources, and this spell, and you have a 4 mana draw 8. Simplicity itself.

I'm trying this out as a 1-of to see how it fits with the deck. With our mana base skewed to black as it is, it's not impossible to get to 5 mana and never see one of our side colors. If we already have our blue and green, then golos can pull a swamp for Dread Presence, or a scryland to find one.

Honourable Mentions

Tatyova would obviously fit quite nicely in a deck like this, providing additional synergy with landfall. However, casting her is difficult given all the black mana sources we run. Maybe sacrificing some of our swamps to make better use of U/G cards could benefit the list.

Again, casting costs restrict me from using Tamiyo, a powerful planeswalker who would synergize extremely well with a deck plan like ours. I would definitely try to fit Tamiyo in before I took Tatyova.

Command and Yarok go together so well, how could anyone not put it in? Maybe we have room for it. Without the explore package, dreadhorde seems a little underwhelming for us. On that note...

and a bajillion explore creatures

It's been done before. Yes, it defined midrange in standard and probably still does. I can't argue that I'm rotation proofing the deck since we lose a few of our key cards in autumn. Maybe if the list had more forests in it I would consider the explore package, I dunno.

Again, tempting choice in colours we barely run. Honestly the effect might be nuts in tandem with a Dread Presence. If anything will push me to adjust the mana base, it's this.

Thanks for reading all of this, or for skimming through it to the end. I'm sure it's a lot of pointless babbling that no one needed in their life. I hope you like the deck and it treats you well. Good luck on your draws!