I've heard of Expedition! You're not the first one to recommend it to me through comparison, which I should probably take as a sign XD there is a kind of worldbuilding through logical inference that forms a niche in SFS that I really enjoy, but I always feel like whenever a thing is billed as an example of it, they're never... quite as satisfying as I want them to be. I want to be immersed in foreign rules and come to understand them through exploration of their ramifications.

Also, there has probably always been some scraplets that are specifically carrion eaters, targeting dead or grievously injured mecha, that have been used for body disposal in areas where constructing sufficient foundries has been impossible (or, y'know, if you're doing crimnal activities). I think, though, that most of the "official" breeding of scraplets was focused on producing more beneficial starands, like ones that could be used to strip paint, clean rust and other corrosion from severe injuries, or to clean fresh welds from slag in a gentler way. It's entirely possible that medical research also produced the hostile strands, but it would take a very mad scientist to create flying piranhas that specifically like living metal, y'know?