I will openly admit to being a pilferer. Most of my mechanics are straight-up stolen or inspired by other games. Something like Animate This! is honestly an anomaly (as in a game with mostly original mechanics), most of the time I just steal stuff at wild abandon. So what games have you loaned mechanics and other things from?
For me, it’s funny, I steal a lot from John Harper, but not from Blades in the Dark. Rather, I have stolen so many things from Lady Blackbird (and the Solar System that inspired it in turn). I especially love the refresh scene mechanic, and have used it in several designs and even tried to homebrew it to stuff like Genesys, with mixed results.
Though, I must admit that generally I just pilfer entire games. My From X to Y series of games (of which From Dungeons to Delving is the first one) is going to be just me taking an old game and modernizing it while being cheeky about it. Then I have Pathwarden, my Pathfinder 2e hack, which, unsurprisingly, is wholly pilfered from that, with some Shadow of the Demon Lord dropped in (which I also reference more often than I admit probably).
My favorite part of pilfering though, is taking a visual style of a game and trying to replicate it! That’s also my specialty for some reason. It’s like a design forgery, honestly.