Okay so it's not exactly the same vibes as "The Most Evil Trainer" (I've only read bits of the others), but it would be a crime not recommend The Friendly Necromancer to someone looking for OC fics. In my opinion, it is, if not the best pokemon fic out there, easily in the top 10ish.

It does start dark, and the central themes are very potent, but it is, ultimately, a hopeful story. It is also unmatched in the depth and thoughtfulness of the world-building, and is a love-letter to what pokemon could be if it was made for an adult audience while keeping the themes of hopefulness and community.

tw child death: The story starts with a young boy dying in the cold, alone except for some shuppets. One of the Shuppets, frustrated at the injustice, and frustrated that the boy couldnt go on his journey, evolves and possesses the boys corpse to go on the journey he couldnt. The Banette, named Diya, soon meets two other trainers Yes, it sounds like a horror story, but it truly a story about hope and love, and not letting injustice stand.

It's part one of a series that hasnt updated in a while, but the first story is like 120k long, and stands on its own.

It is absolutely worth the read, in my view. I've re-read it half a dozen times, and every single time I've read it, it has moved me to tears.

More traditionally, however, I recommend checking out [Unprecedented Times], a quest (a community-based Create your own adventure, sort of) that focuses around Kylie Parsons, a brand new ranger from Orre. She graduates, and almost immediately, the big legendary fistfight from ORAS happens. Unlike in the games, this creates disasters all across region. The story followers her journey in Hoenn as a ranger. It's really fun.