Good question. 7 have won the Oaks-Derby double. Haven’t heard any more than that.
If NO jocks have been aboard two or more winning horses in all three Triple Crown races, it would be obviously an impossiblity for any jock to do what Borel might do if he wins the Belmont: win 4 races (with the first one unofficially considered “the filly Derby”), and then all three Triple Crown races, TWO of them aboard the Derby and Belmont winner, and the other two aboard the Oaks and Preakness winner. THAT undoubtedly would NEVER be done again, for what it’s worth. If Borel accomplishes that , it will be The Year of the Borel, even in China.