For sure - Eric Clapton, Peter Green, Mick Taylor, John McVie and Mick Fleetwood, and I believe Jack Bruce as well. Mayall's bands were a literal breeding ground for super star talent.The list of musicians that came through his band is almost unreal.
In Clapton's autobiography published in 2007, he has an entire chapter about his time with Mayall. Fascinating descriptions of those times playing and travelling to all those gigs around England. They were all real deal road warriors. And it's true, Clapton listened to all those Chicago Electric Blues albums that Mayall had in his collection.