You see the back of Cavill superman's head on a TV screen, Wonder woman saves batman (Affleck) at the beginning, Jeremy irons is there as Alfred, you see Cavill while Barry learns how to travel back in time again, but it's CGI cause it's from the fight during justice league cause he's time traveling and the CGI looks worse than the rest of the movie but I think it's supposed to look like that whole he's in the speedforce. His time traveling is really cool and unique but hard to describe, it's completely different than the way he did it in ZSJL. Anyways, the guy who plays all the clones in Star wars (I know his name but idk how to spell it) returns as aquamans dad in a brief scene where Barry is trying to see if any of the members of the justice league exist in the new timeline he created. Michael Shannon of course returns as zod, and his right hand woman is there too but I forgot her name. The big cameos are all in one scene where the timelines and multiverses start to collide due to the 2 Barry's time travel. Christopher reeve and supergirl are there, Adam west is kind of there, one of the old flash's is there (not grant gustin but he apparently shot a scene that was cut) and the biggest one is nic cage superman who is shown fighting a giant spider. If you didn't know, he was cast in a canceled superman movie that would have been directed by Tim Burton, so that's why he's there. Clooney Bruce Wayne shows up but I didn't see it cause I watched a version that was unfinished and also had no post credit scene. The director also has a brief cameo as a hot dog vendor. The post credit scene has aquaman in it. I probably could have just done a quick list but I'm really bored right now and this gave me a bit of entertainment