Here's a deck I'm working on. The goal here is to get a summon and draw from Darkness Ri-chair-al. In order to do so, I run playsets of low level Dark Monsters, many of which can interact with at least 1 other DARK monster in the deck.
The main threat from this deck comes from controlling Ecdysis Caliguleon while popping any threats with Wicked Shadow Dark Lurker. And when they eventually do out your Cali, if they don't kill you, you just summon another big monster, which late game will often have over 3000 ATK. I find this deck works best for tag duels, as the Graveyard fills much faster. In theory, if you can get 60 cards in the GY, you can have 2 Cali with around 8000 ATK a piece.
Given how small these monsters' DEF are, one of this deck's main weakness is piercing, and to some extent switching to Defense Position. I am running a single copy of Kappa's Gas to aleviate this weakness to some extent. Predator Gunleon is also capable of taking advantage of being so durable. Often times, due to the small amount of heal this deck can do, the opponent can come just shy, allowing you to close out a game this way.
Another small thing to note is that it is nearly impossible to deck out, unless your opponent is running a deck designed to actively do so.
I will probably make some slight changes over time, as we get more DARK support.
Toodles & Noodles,