Some of them are about general coding guidelines and code quality, not necessarily vetting your current PR against specs! There's AbsolutelySkilled with clean-code and clean-architecture. Linking to older version of repo because they seem to be no longer on trunk: https://github.com/AbsolutelySkilled/AbsolutelySkilled/tree/...
I've been creating some rules to help with my Java coding: https://github.com/bitkentech/shipsmooth/tree/main/skills/ex.... These are assembled into a SKILL file when this skill file template is built: https://github.com/bitkentech/shipsmooth/blob/main/skills/ex...