https://www.ecfr.gov/search?search%5Bdate%5D=current&search%...

Or browse by Title 14, Chapter 1, Subchapters F & G (Aka Title 14, Parts 89 - 139)

I'm not vouching for this link in particular, but you can also search for things like Part 91 operator, Part 135 operator, etc

https://l33jets.com/resources/blog/the-difference-between-pa...