I have no idea… I would probably say either The Flash or Batman, but… I could change my mind in a second. Idk. Who do you think has the best rogues gallery?
I would agree with the flash
It’s got to be Batman, right? Each one of his villains is a foil to one part of Batman’s character. Joker is the clown, and Batman the straight man. The Court of the Owls asks the question “does Batman really know Gotham?”. Mr. Freeze is lonely and isolated. The best Freeze stories are either love stories for Batman, or ones where he works with Robin. Catwoman questions Batman’s morals better than any other villain. Harvey Dent is the White Knight and Batman is the Dark Knight. Riddler challenges Batman’s authority as “the world’s greatest detective”. I can do this with literally every Batman villain. I’m not sure you can say that with many other heroes’ rouges galleries.
I’m kind of partial Green Lantern’s rogue gallery as it compliments his character well. Since Green Lantern relies on an alien ring that conjures the emotion of will, the space villain corps he fights are other users or corps of the emotional spectrum such as, Sinestro/Sinestro Corps(Fear), Larfleeze/Orange Lantern Corps (Greed), Atrocitus/Red Lanterns (Rage), Black Hand (Black Lantern Corps) (Death). The Lantern Corps enemies, teach him what emotions are dangerous, and which ones should be controlled. Since he is an intergalactic peacekeeper and protects each sector, he also fights alien threats across the galaxy like the bounty hunter Bolphunga, Kanjar Ro, and Mongul. And since he is human, he fights humanly threats from his own sector in 2814 within Coast City - like Hector Hammond, Sonar. Hammond plays a role into Hal’s relationship with Carol, and his job. Given his infatuation with Carol Ferris and his jealously of Hal Jordan, and in the Geoff Johns run and movie he was working under Ferris Aircraft. His humanly threats or villains are usually shaped by alien or otherworldly tech. Hammond got his telepathy and telekinesis from an alien meteorite, the shark was engineered by Krolotean technology, and Sonar uses otherworldly or advanced tech to design to his sound guns.