Sylvester Stallone was one of the first actors to negotiate a fraction of gross revenue and rights (for Rocky).

edit: I heared the above several times over the years, but it appears it may not be true:

https://www.businessinsider.com/sylvester-stallone-on-never-...

> Wasn't it Lucas or someone who was famous for negotiating ongoing rights / IP ownership, when the studio (in retrospect) drastically undervalued them?

IIRC, it was merchandising rights. Sales of the Star Wars action figures were huge, and my understanding kind of unprecedented.

Alec Guinness made a lot of money by negotiating a percentage instead of a fee.