Honestly, fics that ditch the 'Pokémon League journey' template and actually build an original world around Ash are tough to find but so worth it. I spent ages combing through AO3 tags like 'Alternate Universe - Mythology', 'Ash Ketchum is a Mess', or 'Worldbuilding' to filter out the tournament arcs. One that stuck with me was a story where Ash was tied to the creation trio from birth, not as a chosen one hero, but as a chaotic neutral anchor for reality itself—the author really ran with the lore implications from the movies. Sites like SpaceBattles or Sufficient Velocity sometimes host these more plot-heavy, speculative takes, often crossposted from FFN. You gotta wade through a lot of 'betrayal' fics to find them, though.
My method is to search for a pairing tag you wouldn't normally associate with epic plots, like 'Ash/Paul' or 'Ash/Gary'—weirdly, a lot of authors using those dynamics put more effort into crafting a unique setting for their rivalry to play out in. The romance is often secondary to the original storyline about, say, a war between regions or a scientific conspiracy involving Mew. It’s a roundabout strategy, but it filters for character-driven writing over rehashed gym battles.