User blog comment:Kaestal/Desired Villains (by the community)/@comment-25640758-20161012051221

For Arrow, I actually don't watch it, and I really should. But if I had to choose a villain for Arrow, it would be the Riddler. Despite the fact that he is mostly a Batman villain, Riddler has gone up against the Green Arrow from time to time. Oh, and, he should be played by David Tennant.

The Flash would probably have one speedster and one meta-human as the main villains, similar to S3 with Alchemy and Savitar. I'm thinking Inertia and Blacksmith for S4.

LoT could have Darkseid or Anti-Monitor for S3, but those are way bigger villains, and I'm pretty sure that an Arrowverse crossover would be a perfect fit for them. Perhaps Mr. Mxyzptlk?

Vixen is a show that I don't watch. :/

Supergirl, for S3, should most certainly be about Brainiac. I will literally be shocked if they don't do Brainiac as the main villain. If they don't have him, Doomsday and Zod are obvious picks.

Now, here's something a bit more creative. A Green Lantern show is bound to happen at some point. It's been referenced in many episodes throughout the five shows, and Green Lantern is just so cool. In fact, I believe that it will be announced late this year or early the next. If a Green Lantern show were to happen, I think that the main villain for S1 would be Parallax, with Sinestro finally being persuaded to serve him in the last few episodes of the season. After that, Atrocitus, Black Hand and maybe Larfleeze are good picks.