There are other characters in my story that are Pokemon trainers, too. Don't forget that Mario was one of the Super Smash Gym Leaders. Even though those days are done, these people still grow as trainers. They have obtained new Pokemon and continue to get stronger. I have a list of Pokemon owned by Peach, Daisy and Rayman's friends, Mario, Luigi and Yoshi. Here are the list of their Pokemon from in first 3 Generations:
Mario
Bellsprout Marowak Parasect Sandshrew Poliwhirl Slowbro Graveler Muk Poison
Gligar Sunkern Pineco Heracross Swinub Slugma Granbull Delibird
Glalie Walrein Ludicolo Shroomish Swalot Solrock Castform Surskit Slakoth Ninjask Loudred Pelipper
Luigi
Weepinbell Rattata Poliwag Abra Gastly Tentacool Drowzee Grimer Mr. Mime Psychic/Fairy
Misdreavus Quagsire Yanma Elekid Piloswine Magcargo Mareep Slowking Sudowoodo Rock
Shiftry Vigoroth Electrike Feebas Kecleon Lunatone Snorunt Lombre Duskull Sableye Corphish Banette
Yoshi
Lickitung Chansey Kangaskhan Exeggcute Krabby Cubone Diglett Growlithe Slowpoke Water/Psychic
Magby Smoochum Pichu Igglybuff Cleffa Togetic Spinarak Hoothoot Quagsire Water/Ground
Wurmple Nincada Azurill Swablu Wingull Aron Wynaut Lotad Gulpin Spoink Trapinch Bagon Camerupt
There will be more on this soon.