For pokemon I gotta pull out the sleeper hit Pokemon XD: Gale of Darkness. Gale of Darkness is probably my all time favorite game, let alone favorite pokemon game. Also the soundtrack in Gale of Darkness SLAPS, so if y’all have never heard it before you should go take a listen.
My favorite Mario game is probably Luigi’s Mansion for the Gamecube. Maybe a weird choice, but I played it at a similar time in my life as Gale of Darkness and it was one of the first games I actually fully completed.
And, believe it or not, I’ve never actually played a Sonic game 