Crossover Cover: Criminal Macabre: Final Night - The 30 Days of Night Crossover

Steve Niles' comic series Criminal Macabre and 30 Days of Night already had links to the Crossover Universe independent of each other even before this miniseries definitively confirmed they take place in the same universe. It's also worth noting that one issues shows a photo of Cal McDonald, the protagonist of Criminal Macabre, with Eric Powell's character the Goon,  a reference to the crossover Criminal Macabre/The Goon: When Freaks Collide.

Crossover Covers: The X-Files/30 Days of Night