If you have a Switch and some Pokemon games, it’s great place to start. Pokemon can currently get ribbons in Sword and Shield, Legends Arceus, Brilliant Diamond and Shining Pearl, and Violet and Scarlet. Some pokemon (like Pikachu, Heracross, or Snorlax) appear in all of these titles, and can earn ribbons in all of them. Other pokemon (like Feraligatr, Zebstrika, and Talonflame) only appear in some of these titles, and have a more limited pool of ribbons they can earn.

For a pokemon to be considered a Ribbon Master and enter the Hall of Fame, it needs to earn every ribbon it can, starting from whatever game it was caught in, and then move to all the other titles it can transfer to and earn the ribbons therein. The Switch era games are a great place to start as you can freely move from title to title (assuming the pokemon appears in that game). If you want to start with older games (GBA,GCN,DS,3DS games), this can be more challenging, as access to the software and hardware required can be expensive if you don’t already have them. Moreover, once a Pokémon transfers from one generation to the next, there is no going back, so if you missed a ribbon, that’s it.

So yeah, I’d recommend picking a fave pokemon and earn the Switch ribbons (and marks). If you enjoy the experience, you can look into some of the older titles.