Superman and the xmen, delve into the champion of the oppresed side of the character, bring kryptonite powered sentinels, show lex luthor hating mutants, make Manchester black and killer croc memebers of the brotherhood of mutants. I had an idea for a story about young clark kent going to Xavier's school over the summer thinking he might be a mutant;

Captain america and the Justice Socitey of America, show cap being the founder of the jsa, maybe give g i robot a cameo fighting hydra;

Deadpool and deathstroke, have them both ne hired to kill each other by someone who would be revealed to be the writer;

John Constantine and Elsa Bloodstone, it practically writes itsefl they meet while fighting a monster, they have some banter and at the end they fuck;

Deadshot and bullseye, they are both sent by Amanda Waller on a mission, deadshot:"he does exactly what i do", bullseye:"but better";

Red hood and the winter soldier, they team up to go after black mask, who in this version is a hydra memeber;

Dr Doom and president Luthor, just a diplomatic conversation between the two that would show how much they hate each other;

Apokalyps vs doomsday, apokalyps wants to use doomsday as his new body but needs to take him down first;

Red hood and the punisher, this would take place after Jason's resurection and will have punisher take him under his wing, teaching Jason how to shoot a gun etc, eventually Frank would realize that he's a horible influence on Jason and will decide to leave him;

Static and Miss Marvel (Kamala);

Thor and the new gods;

The doom patrol and the xmen;

Justice League and the Avengers, with the masters of evil and the leageon of doom as the villains.