[Phantasm]

Originally Posted by Drakyrias

Moving away from the singular heroes- villain groups like the Hand and League of Assassins.

Any alliances or mergings?

Not so much a merging, but the Masters of Evil and the Injustice League - as well as groups like the Avengers and Justice League, X-Men and Teen Titans or Doom Patrol, etc. - would likely have members from the other company.

For example, I can see Shadowcat and Miles Morales/Spider-Man as Titans, and Jericho was explicitly called out as a mutant in the New Teen Titans Annual that introduced him during the Judas Contract storyline. Both Jericho and his sister Ravager would make interesting X-Men (actually, I can see Ravager in X-Force or the New Warriors rather than the X-Men).

Throw DC's Blockbuster and Killer Frost into whatever incarnation of the Masters of Evil you're using, and Bullseye and Scorpion into the Injustice Gang. Really, at this point you can pretty much justify any DC villain joining their Marvelous Competition's teams and any Marvel villain joining a team from the Distinguished Competition.

Anyway, for mergers there's the entire line of Greek Gods and Titans of Myth. I'd use Marvel's Ares and Hercules over their DC counterparts, and the DC version of Hera. Herc may or may not be Wonder Woman's father; one version of WW had her formed from the soul of Hippolyta's unborn and unknown child; the only male Hippolyta was known to have had sex with prior to her death was Herc. That alone could make for an interesting inter-company crossover.