I stumbled upon a format called "Filth Casserole" which is basically 50 card Modern Highlander (only one of each card except for basic lands) and I am putting together some decks for testing purposes, building an aggro, a midrange and a control deck. Here are the deck list so far. Suggestions/criticisms wanted.
I quite like the idea of Filth Casserole too. It's too bad it seems to have fallen off a lot of the online community's radar. But of course, that does mean fewer netdecks!
For aggro: I still really like Mogg Fanatic and Rakdos Guildmage, even after all these years. Stigma Lasher can be pretty brutal against a lot of control go-tos (use that Tendrils of Corruption or lose it; permanently cripples blockers like Wall of Omens), but I notice your other decks don't overload on those sorts of cards, so it might not be maindeck level.
Rakdos Aggro
Death's Shadow
Dark Confidant
Goblin Guide
Thrill-Kill Assassin
Firedrinker Satyr
Goblin Bushwhacker
Mardu Strike Leader
Herald of Torment
Mardu Shadowspear
Lightning Serpent
Pain Seer
Tormented Hero
Stormblood Berserker
Avatar of Discord
Rakdos Shred-Freak
Alesha, Who Smiles at Death
Rakdos Cackler
Ruthless Ripper
Ultimate Price
Doom Blade
Shock
Duress
Magma Jet
Dismember
Mizzium Mortars
Collateral Damage
Lightning Bolt
Thoughtseize
Dreadbore
Terminate
Ghost Quarter
Tectonic Edge
Rix Maadi, Dungeon Palace
Blackcleave Cliffs
Blood Crypt
Bloodstained Mire
Sulfurous Springs
Dragonskull Summit
6 Swamp
6 Mountain
Jeskai Midrange
Soulfire Grand Master
Snapcaster Mage
Spellheart Chimera
Mantis Rider
Restoration Angel
Geist of Saint Traft
Baneslayer Angel
Lightning Angel
Blade Splicer
Stormbreath Dragon
Thundermaw Hellkite
Anger of the Gods
Lightning Helix
Jeskai Charm
Electrolyze
Remand
Seismic Rupture
Bonefire of the Damned
Mana Leak
Pact of Negation
Steam Augury
Azorius Charm
Magma Jet
Winterflame
Lightning Strike
Sudden Shock
Lightning Bolt
Path to Exile
Sacred Foundry
Steam Vents
Hallowed Fountain
Shivan Reef
Adarkar Wastes
Battlefield Forge
Scalding Tarn
Flooded Strand
Arid Mesa
Sulfur Falls
Clifftop Retreat
Glacial Fortress
Ghost Quarter
Tectonic Edge
Mystic Monastery
Celestial Colonnade
2 Mountain
2 Plains
2 Island
Mono Black Control
Gray Merchant of Asphodel
Phyrexian Obliterator
Grave Titan
Desecration Demon
Vampire Nighthawk
Vampire Hexmage
Pack Rat
Wurmcoil Engine
Bloodgift Demon
Black Sun's Zenith
Iquistion of Kozilek
Languish
Lilianna of the Veil
Grasp of Darkness
Ultimate Price
Mutilate
Dismember
Doom Blade
Despise
Cruel Edict
Thoughtseize
Bile Blight
Tragic Slip
Duress
Sign in Blood
Read the Bones
Infest
Smother
Ghost Quarter
21 Swamp
As you can see the list are not optimized yet.
For aggro: I still really like Mogg Fanatic and Rakdos Guildmage, even after all these years. Stigma Lasher can be pretty brutal against a lot of control go-tos (use that Tendrils of Corruption or lose it; permanently cripples blockers like Wall of Omens), but I notice your other decks don't overload on those sorts of cards, so it might not be maindeck level.
Mono-black control: Some cards I like for this archetype include Dread Statuary (add Urborg, Tomb of Yawgmoth as well if you want to use swamp-matters cards), Mind Sludge, Ink-Eyes, Servant of Oni, Liliana Vess (her +1 can really add up against control or midrange decks).