Jonathan actually originally applied for Survivor but was cast on TAR.
Let's see, racers who later appeared on reality shows...
Kevin & Drew had a show on Discovery I think it was, and Jet & Cord were on an episode -before they were on TAR!
Either Brian or Greg was on Fear Factor and threw a fit, but that might have been before they raced.
Stassi Schroeder from the Family Edition was later on some show called Queen Bees, then recently Vanderpump Rules
One of Brook or Claire was on some Shopping Hosts reality show (NOT the competition type of reality show)
Connor & Jonathan apparently recently were on an episode of The X Factor or The Voice or something.
Josh & Brent, of course, with Beekman Boys
Travis & Nicole were on some episodes of Untold Stories of the ER, but that kind of stretches the definition of reality show, not to mention this was before they raced.
This is all extremely vague but it might serve as a sort of base. So yeah, not many in reality competition shows, even fewer in shows anyone has heard of, and nobody who later appeared in a CBS reality show. Unless you count Jordan & Jeff who went on BB again after being on TAR. And then I'm not even going to bother mentioning what shenanigans Rob has been up to.