SlimeSage
Just a thought to consider if you're interested. Bunch of randoms: Thundercats Miraculous Tales of Ladybug Power Puff Girls (Older) Ben 10 Gargoyles Swat Kats Sonic Donkey Kong Crash Bandicoot Fighting Vipers Voltage Fighters Virtua Fighters DOA Street Fighter Queens Blade Darkstalkers Harry Potter Adam's Family Avatar The Last Airbender Super Mario The Incredibles Guilty Gear Zootopia Fosters Home Soul Caliber King of Fighters Fatal Fury Soul Eater Tekken TMNT Totally Spies Kim Possible Danny Phantom Looney Tunes Tiny Toons (Older) Animaniacs (same) Chip and Dale Rescue Rangers Goof Troop Cool World Who Framed Roger Rabbit Jackie chan Adventures Inspector Gadget Johnny Test. (Scientists 4 K♡'s) Dexeters Lab (Scientist 4 K♡'s) Big Hero 6 Glitch Tech Iron Giant Witchblade Winx Club Rosario Vampire Rumble Hearts Arcana Hearts Outlaw Star Pirates of Dark Water Aladdin (tv series) LoL Overwatch Maken Ki Ninja Gaiden Anime: (Depending on how powerful the enemies are intended obviously some are a no go. Some also needing the Kingdom Hearts option or crossovers. Doing this all out of order so I know I wrote this more than once.) Naruto One Piece Fairy Tail Bleach Kill La Kill Kenichi Tengo Tenje Ikkitousen Ghost in the Shell Food Wars Games: Mass Effect Metroid Legend of Zelda Chrono Cross WoW FFXI or XIV (to avoid long term story or taking away vital characters) (Mixing some of the series into the same world) Pokemon Perhaps ending in a variation of Kingdom Hearts of your choosing. (Which of course can add other series without adding their worlds. Like Teen Titans, Young Justice, or Batman Beyond without the whole DC verse.) (Same with ones with vital characters and long stories like the single player Final Fantasy games) For more sedate chapters, civilian encounters without making a bunch of OCs while probably horrible choices for the most part but could still be amusing. Can also adjust personalities. Especially due to the change in the world whether crossover or Kingdom Hearts. Also obviously doesnt need to follow exactly. Could just be a similar end result with a scattering/merger. Could be the same but an unknown trigger so the games baddies arent even involved or started to build up, let alone active for a time. Maybe no world devouring at all. Total Drama Island Simpsons Family Guy Cleveland Show American Dad King of the Hill Loud Family Proud Family (original version) Lilo and Stitch Futurama Daria Thornberries American Dragon Jake Long Archer HotD Anything with a bunch of civilians like Danny Phantom and others have.
I'd like to say that if you don't want it to be a harem story, you could have it so that the MC lives a life in your chosen world, dies, and then moves on to the next world to do it all again till he finds the one you want him to be with till the end. Doesn't have to be the first girl he meets in the first world. Read Bokuboys Planes walker story on scribblehub to understand what I'm on about.