The best stories that dig into the core of these two characters often lean into their 'manufactured mirror' dynamic. They were built as a pair, designed to work in tandem, which is a fantastic jumping-off point for exploring codependency, forced intimacy, and the quiet horror of only truly being understood by the one other being you were literally assembled to complement. The most popular trope I see is the 'found family of two' in the wreckage of the pizzeria long after closing, where their only purpose becomes protecting or maintaining each other, often in a bleak, liminal setting. It strips away the performative 'funtime' aspect and asks what's left when the show's over forever.
A lot of writers also go hard for the 'enemies to reluctant partners' arc, which works surprisingly well if you consider their possible conflicting directives—maybe one is programmed to lure while the other is meant to restrain, creating inherent tension. The body horror elements get a lot of play too; stories about one repairing the other's damaged endoskeleton, or swapping parts, blur the lines between mechanical maintenance and something painfully intimate. I tend to skip the outright romantic fluff, as it often feels jarring, but the fics that treat their connection as a strange, poignant symbiosis, born from shared trauma and a dead creator, are where this pairing really sings.