20REVERSE FLASH (EOBARD THAWNE)
When it comes to designing superhero costumes for television and film, there is a major question that has to be asked of all production designers -- how dark do we want to get? When superhero movies were still a relative rarity, the first X-Men film in 2000 said, in effect,
"Remove all possible color!" The X-Men went from the comic book outfits that were filled with colors to the plain black leather outfits of the film. The film even poked fun of the comic book costumes, famously riffing on Wolverine's yellow spandex.
Of course, one of the Flash's biggest villains wore a costume that was precisely that! Eobard Thawne, the Reverse Flash, wore an almost all-yellow costume. Therefore, when Maya Mani and Andy Poon debated the design of the Reverse Flash's costume on Season 1 of the Flash, they initially tried to overload the yellow with lots of extra design elements to tamper it down. Had they gone with that design, it would have likely informed all of their design work going forward on the show.