Seeing YouTube has a limit with words on the description, I'll just explain The Mizfitz Enemies "The Legion of Doom" Here
The Mizfitz are already "Bad Guys" with their naughty and wicked ways, but even they have enemies, so can say it's Bad Vs. Evil or better yet, Wicked vs. Evil HaHaHaHa
Pitch Black - The Started of The Legion of The Destroyers, he started his own Squad, after seeing how strong his brother is with his fellow Mizfitz, so maybe with his own Squad he can manage to defeat The Mizfitz and fullfill his destiny in becoming The Lord of The Underworld.
Killian - Lance wasn't the only responisble for turning Killian into a second "Two Face" and seeing how much he hates The Mizfitz, Joker recrutied him
Emperor Palpatine - Just like how Ralphie brought back Darth Vader from The Dead, his little brother did the same with Vader's Master, so The Emperor can train The Destroyers to master The Dark Force.
Doctor Robotnik - Joker need an evil genius who build him a robot army and who better than "Eggman" himself, and hearing that Sonic is one of the mizfitz, he was more than pleased to join
Jafar - Tired of being second best to Hades, he decided to team up with Pitch Black who also wants to be rid of Hades, but he knows Hades can't be touched, especially with Hades' son and his group of Mizfitz, but Jafar is the only villain who manage to "kill" Ralphie, or so we thought, but Jaffy was defeated by a Mizfit you wouldn't expect, Homer Simpson who was lucky enough to get his hands on the lamp.
Fairy Godmother - A Perfection Manic, She hates that ''bad guys'' like, The Mizfitz who has Poison Ivy, Harley Quinn, Loki, and Especially The Spawn of Hades and Maleficent, always win, she wants to make sure every villain looses, even The Mizfitz, just as it's told in the book, her books, that is! She also has bad blood with Merlin, so she trying to berid of his Granddaughter is no suprise lol, Wow She hates villains, yet herself is a one, talk about echomanic, eh? and of course Prince Charming and Rumplestiltskin are her henchmen
Azula - Ralphie's ex girlfriend, need i say more? Ok I Will, Once Upon a Time, there lives an Evil Fire Lord who had a Beautiful Evil Queen, Azula, who planned to Rule of All of The Fire Nations, Until One Day, A Ice Queen Froze His Heart and Turned Him Good, Which BrokenThe Evil Fire Queen, or should we say Ex Queen's Heart That She Went Even Crazy, well, Crazier, Yeah That's Right, That "Evil Fire Lord" was Ralphscoe. HaHaHa Azula is the MOST Craziest Ex's,if their was a Leauge of Ralphie's Evil Exs she be the leader, I mean she would Destroy The Mizfitz and all of Ralphie's friends and family, just so she can have him, all to herself. (Heads up to ATLA Fans, this took place years after Zuko defeated Azula, Azula was like in her midtweenties when she met Ralphscoe)
Cheetah - Wait, I think there is a leauge of Ralphie's Evil Ex's, Because Here is Another One of Ralphie's ex's, Cheetah, she be in second command teehee. Azula tricked her to help, by saying the two will have Ralphie all to themselves, even as a slave as part of their revenge, but there's a difference with her, she doesn't want to destroy Ralphie's friends, family and fellow mizfitz, except for two, the two who stole him away from her, even when Ralphie was Ralphscoe, Selena did the deed in that time. Also him being related to Wonder Woman is a sweet bonus of revenge.
Hecate - A enemy of Ralphie's family, since she too wants to be rid of Hades and his family, so she can rule The Underworld, well, except for Pitch Black, in fact the two partner up and created the this legion.
Pete - All he wants from The Mizfitz is to own their home, The House of Mouse and All of Toon Town so he can boss every Toon and even The Mizfitz around.
Ratigan - Let's just say, he is Pete's Boss and wants to have The Mizfitz and Every Toon in The Universe to Be His Slaves, Yeah, He's worst than Pete
Dick Dastardly - Mainly want to seek his revenge on The Mizfit Angels for helping Scooby and The Gang foil one of his plots, actually there were more than one plots that the mizfit women took down, Daphne is by the way a honorary Angel, Velma would be too, but she got trapped with the boys, so with Daphne helping The Mizfit Angels they manage to take down, Dastardly, more than once lol
Sa'Luk - May be a mortal man, but he manage to beat some Mizfitz, hand-on-hand battle with just his fist, with a little help from his claw, he seriously must have god strength, no? ok.
Mirage - believe it or not, Mirage hasn't always been a kitty cat, it was The Mizfitz fault she was transform into a cat for all eternity, which does explain why she wants to destroy The Mizfitz, that's pretty much all she wants.
Mr. Burns - Just a Greedy Old Man, who try to buy the most popular club, House of Mizfitz, so he can be in charge of The Mizfitz, especially The Simpsons, but was rejected, so now he seeks revenge on The Mizfitz, just because they said no, plush Joker is using him for his money XD
Slappy The Dummy - even though he is a Mizfit Trainee, The Mizfitz still don't trust him and how can they after all the goosebumps he put them threw, he's literally the biggest fear of The Mizfitz, especially their leader.
The Joker - The Leader of The Legion of Doom, but He doesn't want to kill The Mizfitz, oh no, nope. The Joker and Ralphie goes way back, since the day of Ralphscoe, once Ralphie reformed he really made The Joker more mad than ever was, so one way or another he will get his friend back, plush he's not too happy that Harley left him for Ivy, so yeah he got that going
Hela - After hearing there's a god of the dead, she wants to be his queen, so she and him can rule both the living and the dead together, yeah, Ralphie may have evil exes, even some crazy stalkers / crushers, but they don't compare to Hela and her goal in becoming The Goddess of The Dead, since Ralphie told her "there's only one god of dead around and you're looking at her, babe!"
Thanos - The Stronger Enemy of The Mizfitz and Formally was the leader, but since Ralphie took his Gauntlet, He is Partner up with The Joker, Now he himself has one goal, to get his Gauntlet Back, so he can complete his destiny and wiping out half of humanity, and all The Mizfitz are on that half... well, the good mizfitz at least...
The Legion of Doom - with the help of his new friends, Joker manage to become the leader of The Legion of Doom, so not only are villains like, Black Adam, Grundy, Sinestro, Black Manta, Giganto, Ma'alefa'ak, Metallo, Mirror Master, Star Sapphire, Scarecrow, Riddler, Two Face, Penguin, Bane, Killer Croc and, well you seen The Legion of Doom, you know the rest, along with Joker's new friends, this will be on incredible army of villains to beat, good thing The Mizfitz and The Justice Leauge has an alliance... even though a couple don't get along, but they put away their difference when they have to deal with these villains.
Doctor Pyscho is a questionable, but we'll find out in season 3 of Harley Quinn series, but my money is he's in The Legion of Doom
Bonus (Youtube: no room to add em):
Freddie Krueger - Only threw Nightmare and only dealt with Ralphie and Princess Luna, while Princess Luna try to spread happy Nightmares with the help of her assistant and fellow Mizfit, Ralphie, Krueger is right there, ready to destroy what they create, no one hate him more than Princess Luna!
More To Come...