Anime Superhero Forum

Considering that the title "OK K.O.! Let's Be Heroes: Let's Fight to the End" was discovered on TCM.com (the title has sadly been removed now), there's still a chance for a third (and final) season.

Maybe, but "Dark Plaza" felt very series finale-ish.

I would be sad if it didn't get a season 3

Not Yet though, considering that was when i felt about WBB, since they mention a TV Flim and a Baby Bears Spin-off by next year with no mention of season 5.