How about a crossover with 'Steven Universe'? The characters from 'Final Space' could visit Beach City. Gary might befriend Steven and they could fight some corrupted gems together. The Gem technology could be something that the 'Final Space' characters are intrigued by.
A 'Final Space' and 'Star Wars' crossover fanfiction would be cool. Quinn could use her skills in the Star Wars universe. The Crimson Light could be like a small rebel ship, and they might have to face off against the Galactic Empire. Gary could learn some Jedi - like moves from the Force - sensitive characters in Star Wars.
One idea could be a crossover with 'Rick and Morty'. Gary could team up with Rick and they'd have some wild adventures across different dimensions. Maybe they'd encounter some new alien species together that are a combination of the creatures from both shows.
One idea could be creating an OC who is a skilled mechanic from a far - off planet. They could join the crew of the Galaxy One and use their unique mechanical skills to fix and upgrade the ship in ways that the others can't. Maybe they have a special tool that was passed down in their family for generations.
One idea could be a crossover with Street Fighter. Imagine the characters from Final Fight teaming up with Ryu and Ken to fight a new, powerful villain that threatens both their worlds. The different fighting styles would create really cool battle scenes.
One idea could be a crossover with the 'Harry Potter' universe. Squall could be a wizard, and his gunblade could be enchanted. Another could be a crossover with 'Star Wars', where the characters from Final Fantasy 8 are in the middle of the galactic conflict. Maybe Laguna could be a Jedi - like figure.
One idea could be a crossover between Final Fantasy VII and Final Fantasy X. Imagine Cloud and Tidus teaming up to fight a new powerful enemy. Another could be a crossover with a non - Final Fantasy franchise like Pokemon. Picture Squall trying to catch Pokemon in the world of Final Fantasy VIII.
Well, a cool space marine crossover fanfiction idea could involve crossing them with superheroes. Picture a space marine teaming up with Superman to fight an intergalactic threat. Or perhaps a crossover with the Predator universe. The space marines' combat skills and high - tech gear against the Predator's hunting skills would make for an exciting story. Also, a crossover with the Warhammer Fantasy world, bringing the space marines into a world of magic and medieval - like warfare.
A crossover with Stargate SG - 1 could also be fascinating. The Goa'uld and the Taelons both have an interest in power and domination. The SGC could get involved when they notice the Taelons' activities on Earth. They might try to figure out if the Taelons are another alien race like the Goa'uld or something entirely different.
A 'Final Fantasy VIII Crossover Fanfiction' could involve crossing it with the world of 'Alice in Wonderland'. Rinoa could be like Alice, falling into a strange world where everything is topsy - turvy. The Heartless from Kingdom Hearts could also be added to the mix in a crossover. The characters of Final Fantasy VIII would have to fight these new enemies, with Squall taking on the role of a keyblade wielder in this strange new world.
One idea could be a crossover with the Warhammer 40K Imperium forces where a group of Chaos Space Marines infiltrate an Imperial stronghold. They could face off against Space Marines of the Ultramarines chapter, leading to intense battles and moral dilemmas for both sides. Another idea is a crossover with a fantasy setting like the Elder Scrolls. The Chaos Space Marines could find themselves in Tamriel, causing chaos among the different races and factions there. They might encounter the powerful mages or the warrior guilds.
One idea could be a crossover with another popular RPG like Dragon Quest. The characters from World of Final Fantasy could end up in the world of Dragon Quest, facing new enemies and having to adapt to different magic systems. For example, the mirages in World of Final Fantasy might interact in strange ways with the slimes in Dragon Quest.
A crossover with the Star Wars universe could also be exciting. Imagine the characters of Final Fantasy 13 in a galaxy far, far away. Snow could be like a Jedi, using his strong will and combat skills, while Fang might be more of a bounty hunter type, roaming the galaxy in search of valuable prey.