And thank you for the offhanded mentions of those systems. Dogs in the Vineyard sounds fucking wild and I'm definitely going to give that a look.
There is so, so much more out there than D&D.
Blades in the Dark: Play a gang in a setting that is basically Victorian London with ghosts. System is very, very simple - I would say too simple personally, but a lot of people love it.
Deadlands: Horror western where the Civil War never ended because native Americans summoned demons. You can secretly be a zombie and not know it. The wizard-equivalent class is a card-shark who learned that the rules of poker are a coded secret ritual to make a deal with the devil. Have to play blackjack against Satan every time you want to cast a spell.
Delta Green: Call of Cthulhu but you work for the government. Has three settings: the "Agency" Era (fully-fledged government department, 1928-1970), the "Cowboy" Era (the agency has been disbanded, but you didn't stop fighting, 1970-2001), and the "Program" Era (Post-9/11 antiterrorism legislation quietly reactivates the agency. The Cowboys don't trust the new Program, and so operate simultaneously. Which one do you actually work for? 2001-Present). Clunky system with some cool adventures, like "The Last Equation" where the villain is a math problem.
Night's Black Agents: You're spies who accidentally discover a supernatural or otherworldly conspiracy - the game and its rules are highly modular, as in each section of the rules has four "options" the GM can pull from to tweak the feel of the game, tons of options for the setting, highly unique every time its played.
Paranoia: Very silly game. You're clones living in a massive facility run by a corrupt AI that is somewhere between GLaDOS and Clippy.
Ten Candles: Simple one-shot horror game. Very few mechanics, zero prep. Light ten candles, use ten d6s. Any time any player wants to do something, roll all dice. If they get even one six, they succeed. Any dice that roll a one get taken away. If they ever fail, blow out a candle. Move to the next scene with 9 d6s, etc.. "Character Sheets" are a stack of notecards with character traits that were established collectively. Players may automatically succeed (or get a reroll, I don't remember) by burning one of their cards. The final card is their name, and requires their character to also die.
Twilight 2000: Hexcrawl through wartorn Poland or Sweden if WW3 took place in the nineties.
There's a ton of stuff out there. Maybe just spend some time skimming something like the big list of stuff on 1d4chan (now 1d6chan for soy reasons):
https://1d6chan.miraheze.org/wiki/Category:Roleplaying