Okay, so hunting for good Denki Kaminari x Reader stuff feels like it's gotten trickier lately. A few years back, Tumblr was absolutely flooded with them, but the algorithm changes and the whole purge thing really scattered the community. These days, my absolute bedrock is Archive of Our Own. The tagging system is a lifesaver – you can filter for exactly what you want, exclude what you don't, and the quality is generally higher because people actually put effort into posting there. I've found some genuinely sweet, in-character stories that really capture his dumb-smart, golden retriever energy.
That said, don't sleep on Quotev. It feels kinda old-school, but there's a dedicated crowd there that still churns out classic, tropey reader inserts that hit that specific nostalgic spot. It's less about literary masterpiece and more about that quick, satisfying hit of 'what if I were there'. Wattpad is... a mixed bag. You have to wade through a mountain of poorly spelled, OOC stuff to find the gems, but they do exist! I follow a couple of writers who migrated there from Tumblr, and their stuff is solid. TikTok and Instagram are weirdly good for recommendations though – people make those aesthetic edits with snippets of fics, and that's led me to some amazing stories I'd never have found otherwise.