#3: Star Wars and Aliens
Xenomorphs would wreak havoc in the Star Wars universe. Would lightsabers cauterize wounds to the creatures to prevent their acidic blood from destroying everything? Would blaster fire? Maybe they could be controlled to serves as biological weapons for the Empire. Something tells me though, that they would simply be a menace to the galaxy, to the Rebellion and Empire alike. I would want to see this among Star Wars crossovers just for one reason: a Darth Vader hallway battle (like in Rogue One), but with xenomorphs.
#2: Star Wars and Battlestar Galactica
This one perhaps isn’t out of the realm of possibility for Star Wars crossovers. Both stories take place a long time ago, and in galaxies far, far away. Imagine if a Galactica jump goes awry and the ship finds itself face to face with an Imperial Star Destroyer. Perhaps they’d encounter the Rebellion fleet, which could integrate the Battlestar Galactica rag-tag collection of ships into its own. Just image it: Vipers versus TIE Fighters.
Topping the list of Star Wars crossovers is, naturally….