Crack: Summon all 18 Project Voltage Pokemon type Hatsune Miku with their Pokemon to the Re:Zero world and chao. Best showing of their relationships and some of the stuff that they did is in Glorious Day(Could add the 2 extra Hatsune Miku from the song to this insanity). (I guess Satella is a fan of Hatsune Miku in this scenario) For extra crack, you can make 'em all royal candidates, or at least the Dragon one(more candidates?). For things that warrant reactions from the Re:Zero world public, we have the various modern outfits and tech, Pokemon and stuff that goes with them(ex. Pokeballs), how they all know a different written language and how that language is on some of their clothes, how most of their hair is, especially the ice hair, and how one of them is a ghost(or ghost-like powers?) and another one is a psychic. At some point, could have any of them have a performance that is them recounting the story of any well-known character or Pokémon in song form, such as the ground and/or flying ones doing the entire Rayquaza legend then transitioning to the story of them going to Sky Pillar and running away from Rayquaza and/or could do any of the protagonists' journeys. They could try to teach Emilia how to sing? Could also add the one from After Epochs to this, she listens to the music from the others.
Miku teams as I pieced them together:
Psychic: Meloetta, Ralts?, Kirlia?, Gardevoir?, could add Abra??
Grass: Rillaboom, Steenee?, Bellossom?, Maractus?, Hoppip?, Skiploom?, Jumpluff?, Gossifleur?, Cherrim?
Fire: Skeledirge, Crocalor?, Marowak(Alolan)?
Water: Primarina, Brionne?, could add 1-3 Pyukumuku and/or a Wishiwashi??
Electric: Rotom, Mr. Rime, Electivire, Heliolisk, Jolteon, 2nd Rotom(seems to also have Rotom appliances, Rotom Catalog?), Zekrom?, Yamper?, 3 Dedenne?
Normal: Chatot, Exploud?, Spinda?, Smeargle?
Ice: Lapras, Iron Bundle?, Delibird?, Vulpix(Alolan)?, Froslass?
Rock: Aurorus, Diancie?
Ground: Flygon, Vibrava, Trapinch, could add 1-2 Cacnea, a Rufflet, a Sandshrew, and/or a Nosepass??, Silicobra?, Zygarde(50% with Power Construct)?
Flying: Altaria, Rowlet, Swablu, Dragonair, Castform, Noivern?, Trumbeak?, Swanna?
Fairy: Jigglypuff, Igglybuff, Ribombee?, Comfey?, could add Snorlax(from additional illustrations)???
Bug: Kricketune, Shedinja?, Volcarona?, Sewaddle?, 2nd Sewaddle?, could add 1-3 Kricketot??
Poison: Toxtricity(Amped), Magnezone, Trubbish, Muk(Alolan), Toxtricity(Low Key)?, Grafaiai?
Ghost: Mismagius, Pumpkaboo?, Gourgeist?
Dark: Obstagoon, Honchkrow?, Murkrow?, Houndoom?, Houndour?, Politoed?, Poliwhirl?, Poliwag?
Steel: Jirachi, Bronzong?, Meowth(Galarian)?, Spiritomb?
Fighting: Sirfetch'd, Farfetch'd, Farfetch'd(Galarian), Gallade?, Lilligant(Hisuian)?, Hitmontop?
Dragon: Miraidon, Jangmo-o?, Hakamo-o?, Kommo-o?
Glorious day Cute: Raichu, Milotic, Volcarona, Decidueye, Glimmora, Gardevoir.
Glorious day Tough: Charizard, Dragonite, Metagross, Haxorus, Quaquaval, Garchomp. (Note: She has the Galar Dragon gym badge, so she beat Raihan, so she is champion level in the regions that he could've moved to and be strong enough to be champion. Could justify giving a Dynamax Band because she needs a Galar League Endorsement in order to fight their Dragon gym, probably also beat the previous gyms in order to qualify to fight that gym, thanks to him being known as the strongest gym leader in that region, Galar League does cycle out weaker gyms so the gyms that she fought could of been different and/or in a different order, unsure when in the journey she would've got the Dynamax Band if she got one. Dynamax and Gigantamax cannot be used even with a Dynamax Band unless in a Power Spot(existance of Galar Particles), so the object is useless if no Eternatus in the region ever.)
After Epochs Miku: Jigglypuff, Lapras, Porygon2, Farfetch'd, Lopunny(able to Mega Evolve), seen with Mismagius, could headcanon Ho-oh.
Could add means that they were seen with them in concept art, but it is unknown if it is a wild one or their caught Pokemon/they caught them after the scenario in the concept art happens, ? otherwise signifies that I got it from the additional illustrations. There seems to be some Pokemon type versions of other Vocaloids(Ex. Electric Rin), other versions of Miku(ex. Blueberry academy Miku, other ghost Miku), and regular versions of Miku and other Vocaloids seen in some additional illustrations and music videos, but I am not listing their teams for various reasons. For the Miku that have over 6 pokemon, I think that some of 'em are just in the PC or something. Note: At one point in Masters EX, someone awakens Jirachi and wishes to open an Ultra Wormhole for a loved one to get home from another world and they follow their singing back through it, so that may be relevant to the Steel one. If you feel like it, you can headcanon some to all of the Miku visited Pasio and therefore each received a Sync stone, and therefore can use a Sync move, which sometimes includes Mega Evolution or a Z-Move as part of them happening(one of the additional illustrations is Psychic Miku and Rosa who's in a Masters Costume, Mega evolution point unnecessary with After Epocs Miku). An extra thing that can be added is having Subaru(if he's here) and Al be from the world of Pokemon. Subaru may lolimancer some of 'em? The Miku can refer to each other by Type or Trainer class? Would be hilarious if Steel's Poke Flute awakened those suffering of sleeping beauty condition.

YOU ARE READING
Some Re:Zero fanfic ideas, crossover mostly
FanfictionThis was originally a big Sonic X Re:Zero fanfic idea, adding other ideas here that I felt were worth keeping. Ideas originally posted to Reddit by me(will update every so often), spoilers for stuff beyond S2 will be here, but after a warning that c...