DC Super Friends, on Mattel.com / DC Kids (YouTube)
IMDb; TV Tropes; YouTube

I guess this maybe originated on home video, I'm not sure. Some sites mention 7 episodes, which were released in 2011-12, but I believe that's an entirely different series, which aired on Nickelodeon. Wikipedia also mentions a four-episode webseries, which is also different from what I watched. I first saw this series on YouTube in 2017, and there are 15 episodes. (They were released on the DC Kids channel in 2015, but I'm not sure if they're on that channel anymore. However, I've changed my links above to a playlist on Imaginext's YouTube channel.) I guess the series is sort of spun off of the 2010 DVD episode The Joker's Playhouse, which was packaged with some toys. So, maybe these shorts were packaged with toys, too. I dunno. Anyway, the Joker falls on hard times, and teams up with Lex Luthor and the Legion of Doom. Meanwhile, Batman has recently taken Robin on as a partner. And Superman tries to get Batman to join the Super Friends (or Justice League, or whatever). Despite Batman's reluctance, he does finally have to work with the Super Friends against the Legion of Doom, which is using a transporter ray to steal major world landmarks, and stuff. That's pretty much all I want to say about it, but it was a reasonably fun little series.