Crossover fiction
placement of two or more otherwise discrete fictional characters, settings, or universes into the context of a single story
Endless Winter
Versailles, Burning with Love
Batman v Superman: Dawn of Justice
Superman/Batman: Public Enemies
Full Moon Over Miami
Lab Rats vs. Mighty Med
Invasion!
Flash vs. Arrow
Heroes Join Forces
The Spectrum War
Dimensions in Time
Superman/Batman: Apocalypse
Crisis on Earth-X
intercompany crossover
Crisis on Infinite Earths
Mario & Sonic
Planet X