Sonic Pokemon headcanons! (with the sssumption that theyre IN the world, not playing just the games)
I know Sonic is terrified of water but do you think he'd primarily use Water and Electric type Pokemon? He'd always be like "I'm telling you it's NOT just because I'm blue!!!" Despite his fear of being IN water, he actually sees Water type Pokemon as very pretty! (and also, Water types can carry him over water or help him in a pinch, if he falls in). If not Water types, then I'd say Flying types, as they're also very cool and very fast usually! He has a few Dragon and Ice types too.
I can see Shadow using Fire and Psychic type Pokemon, and some Dark types here and there (mostly Dark-Fire types though). Psychic types because he's somewhat weak to the very alien-esc nature of them, and also Mewtwo. He just... Mewtwo is his buddy okay? (Also he'd help look after Amy's Grass types and Normal types from time to time). Oddly enough I'd almost say he'd have the most balanced sort of team. Also, he has an Oricorio (Sensu style) who started following him around after he visited one of the grottos of Alola with lavender fields. The Pokemon doesn't battle at all, and he hasn't even caught them, but they do enjoy being around Shadow quite a lot and help comfort him when he has anxiety attacks. Shadow likes to call them "Marmar", which they seem to respond well too also.
Rouge uses all the Pokemon that look like bats really, lol. She also shiny hunts often. She probably has a Sableye, and she also like Rock types that are SPECIFICALLY shiny and like gemstones (she's still convinced the crystal Onix exists)
Tails uses Steel and Electric types, he trades Sonic perfect-IV and EV electric types for variants of Pokemon he doesn't have yet. He's the one collecting every Minior and shit lol, and also is the one to be doing the breeding and competitive-set creating. Also he has multiple Vulpixes and Ninetailses because they make him happy. He has like... One or two Flying types that came from Sonic, also.
Knuckles plays the game like we all did as kids, he gets rid of ever stat-changing move to replace it with the strongest attacks he has access to, then proceeds to fail many times and questions why. He uses Rock and Fighting types mostly, of course.
Amy uses Normal, Fairy, and Grass types, though she doesn't battle much and instead helps Tails to breed Pokemon and keeps a huge garden where many Grass types relax in peace. Shadow helps her take care of it when he visits, and many of the Skittys she has have taken a liking to him (and his Purrloin).
Omega strictly uses Steel and Electric types that are, in some way, robotic.... And by uses I mean has somehow managed to directly connect to and communicate with them. He doesn't even catch them, they just basically Bluetooth sync to him and they all go "Let's kill shit".
At some point Sonic goes into that fuckin cave place where you find Mewtwo, preparing to finally battle them, and ends up finding Mewtwo and Shadow just fucking chatting while sitting on some rocks and is just like
Shadow's like "Dude we're in the middle of a conversation either join or leave"
Shadow brings Marmar to meet Amy for the first time and, Amy being one who can probably understand normal Pokemon talking or some shit like that, tells Shadow why they'd even originally taken a liking to him, which was because he shared the same colors as their old partner, a Baile style Oricorio. The two used to dance together in the trees, until one day, the other never returned. When Marmar had gone to the other's own flower field to search for them, they found it to have been destroyed, either by a raging Pokemon, or by people. They'd been left quite lonely, since then, and finding someone quiet like themself, who had the same colors as their lost partner, brought them comfort they hadn't felt in a long time.
Shadow probably ended up crying hearing that to be entirely honest, I mean, they'd both lost someone they'd cared deeply for, of course it would hit him hard.
Rouge attempts to "steal" Knuckles' pretty Rock types but it ends up being more like she randomly takes them to get a bunch of treats and then they go back to Knuckles once he finds out lmao. She ends up having a whole family of Carbink living with her too.
Despite her seeming selfish to outsiders, she's actually incredibly caring to her Pokemon, and even others' Pokemon when needed.
Sonic get electrocuted regularly by his Electric types to a point where Tails has become genuinely concerned for his health, like actually properly worried about him, because he CONTINUES to walk it off like it's nothing. Which is normal, but still.
One of Sonic's favorite Pokemon of his is his trusted Manectric, which Shadow likes to joke about how similar the fur of the Manectric is to his own quills and teases Sonic about "playing favorites" as a result, which tends to get him strangely flustered and defensive.
