I don’t have a definitive list, but 2 that are interesting to me in The Internet:
Neil Clark Warren, CEO of eHarmony. I believe he was ~65 when he founded eHarmony in 2000. He took nine figures out in cash, retired … and then came back as CEO again in ’12. Bad arse.
Dave Duffield, co-CEO (and then Chairman) of Workday. Ok, he was already a billionaire or so from Peoplesoft. But co-founded at 60+. Bad arse, again.
Both had a lot of domain expertise in their space … they weren’t starting from scratch 🙂