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Wait a sec. Why am I doing Tracey!? He didn't do anything much!
...yet this is exactly it. This'll take five minutes, tops. Here's what Mr. Filler Season's got.
After a group of punks are harassing a Lapras and Ash challenges them, Tracey takes it upon himself to gauge their Pokémon. In doing so, Ash's Pikachu shocks him. He introduces himself, uses one Pokémon to help, and then invites himself along for the Orange Islands journey.
The group helps a glass sculptor realize his dream by finding the Crystal Onix, and Venonat proves not to be useful, since it finds rock formations... So Tracey sends out some auditory help in the form of his Marill!
Wild Scyther are fighting, and their old leader has been ousted. So it doesn't die, Tracey captures it and takes it to the Pokémon Center. After healing and kicking Team Rocket's asses, it decides to go with Tracey.
...yep, that's it. Then Tracey sits in Pallet forever. But!
Sometime in mid-Hoenn...
Tracey's Marill gets it on with some Pokémon in the Water 1 or Fairy egg group (I personally blame Misty's Corsola...). An egg is made.
Then he gives it to Misty. Does she really need another one of those?
...well, yes. Since Togepi's gone off to protect the Mirage Kingdom, Misty has nothing to baby anymore. So Tracey's still got the same old same old... for almost 400 episodes. Jeez.
He's just gonna stay in Pallet, undoubtedly. Maybe Marill will become an Azumarill, or Scyther will become a Scizor, but I doubt both. He's gonna end up doing with his Pokémon what Oak did with his...
Keep them in their Balls FOR FREAKING EVER.
Good going, Prof.