So what crossovers you'd like to happen that hasn't happend yet? Even if Marvel and DC won't work with each other anymore, you never know. Here's my wish list.
Batman/Wolverine
Superman/Supreme
X-Men/Doom Patrol
Lobo/Ghost Rider
The Crow/Vampirella
Black Canary/Black Widow
Swamp Thing/Man-Thing
Wonder Woman/She-Hulk