The macOS Terminal offers deep customization via 'defaults' commands, but they're poorly documented and risky to experiment with.
Create a community-maintained site with searchable defaults commands, ranked by safety and usefulness. Include before/after screenshots and version compatibility data.
Monetize through affiliate links to Mac utilities or premium features like change tracking.
Start with crowdsourcing the existing fragmented lists into one database.
Risk: Niche audience, and Apple could break compatibility with any update.