Doom and the Joker are absolutely nothing alike.
If you want a character that at times shares characteristics of the Joker it has to be Green Goblin or carnage.
The J-man
Loki was our Joker, imo. But my vote is for Darth Vader. He's a version of Doom with a less ridiculous backstory.
Errrmmm.... venom.
Pretty much any Marvel villain can pull off a movie like this.
It's not hard, just make an Oscar-bait movie, slap a popular character's name In it and superficially add in their motifs so it gets attention.
That's all Joker's doing
before joker, marvel already had venom , a standalone marvel villain movie
Venom is an anti-hero there though. An edgy weird dude who fights someone worse than him.
Whereas in Joker 2019...not to get into spoilers,
spoilers:end of spoilers
but the movie shows Joker as a villain.
So if Joker becomes a success, it would open more doors, you know.
The Purple Man could be a great dark story.
Sabretooth would also be a great story if delved into the right way.
And a dark Arcade story would work brilliantly with a young X-Men cast to torment.
Killmonger from MCU
Wilson Fisk (base the movie on "Parts of a hole" story line)
Possibly Bullseye
Possibly Elektra (this could be action packed)
Magneto
Apocalypse
Cottonmouth (from Netflix Luke Cage)
Bushmaster (from Netflix Luke Cage)
For it to be as gritty as Joker, I fell it would need to be a street level or militant villain. Let's see how "Loki" does on Disney Plus.