I never got the appeal of Matt and Edd as a ship, to be honest. The fics that focus on their friendship dynamics are way more interesting. A lot of them use the contrast between Matt's impulsive, attention-seeking energy and Edd's more measured, creative personality to explore really solid platonic bonds. You'll find stories where Matt's schemes push Edd out of his comfort zone, but Edd is the one who has to logically patch things up afterward. That push-and-pull creates a kind of mutual dependence that's different from romance; it's about balancing each other out.
Sometimes writers dive into the history, the idea that they've known each other forever. That long history lets authors play with nostalgia and shared secrets, which adds layers without needing romantic tension. You see Edd tolerating Matt's antics not out of obligation, but because he genuinely gets something out of that chaotic energy—maybe it sparks ideas for his animations. And Matt, for all his self-centeredness, often shows a weirdly fierce loyalty to Edd that feels more genuine when it's framed as a deep, flawed friendship.
The best ones don't shy away from the friction. They let Matt be genuinely annoying or let Edd snap, because that's what makes the eventual reconciliation or understanding feel earned. It's less about 'will they or won't they' and more about 'how do they put up with each other, and why do they keep choosing to?'. That's the core a lot of writers latch onto.