Khaall
Can he get a ryhorn because that pokemon is one of the bettery ground type out there you should also make a thing about a trading center where it is place you post a pokemon you want for one that you just captured and the other person might make a trade but rare one will never go to those type of place so that way the main character will not just randomly happen apron a different regional pokemon an less they are from johoto because it right next to Kanto or if it is a water type that might appear around the watter
If the MC is sad about his insider knowledge not being as useful maybe he could study pokemon moves and try teach pokemon moves they can't learn in the games. Lanturn or Ampharos can't learn Tail Glow in the games, probably because its OP and would ruin competitive gaming. Or use his knowledge like pokedex entries to learn pokemon psychology and attitudes and maybe become a professor. Or maybe become an E4 member or Gym Leader
Author, just a little idea of mine, but how would different moves affect roll out? Here are some ideas for this. Iron defense changes the move to steel type(and adds more weight) but build up is slower. Bulk up can maybe make the build up faster but easier to interrupt. Rapid spin makes the Pokémon immobile for a brief period but then roll out become unstoppable in exchange. And finally, acid armor makes the move poison type with a chance to poison.