To the best of my knowledge no-one has ever used my sprites in a game, or if they have they never asked. Though I never mentioned it a fair few of them are actually portraits of friends of mine and/or fanart/gifts of their OC's, I just never mention that because they aren't on here. As for it looking like they could be in the game, I'm glad to hear that.
I do try to keep true to the games with the colour choices, plus since finding the exploded trainer parts sheet I've been using that a lot to create bases of my own and then adjusting/scratching parts as needed before customising the attire and so on.
Though to expand on the looking like they could be in games part, the Sonic style stuff (including the little heroes) is done in a Genesis-esque style I've been using for over a decade now so I've had time to refine the shading method for uniformity. The ships were actually custom graphics for my own units in BattleTech, so I kept to the shading/art style established by one of the biggest contributors to the PC fangame/client for that (though I dislike those sprites now and need to figure out my redesigns).
The micros are simply personal projects, though similar to dolls in the fact that I use bases for those. That said I haven't credited anyone in regards to that simply because I use a highly personalised base these days and other than the base pose, the shading and everything else is typically my own.
EDIT: Because I'm feeling like it, five slots are available for a custom trainer sprite. Feel out the template in the first post and first come first serve.