Apologies if this overlaps an existing thread. I know that there are some that are similar out there, but I'm looking for something specific here.

Having grown up on 70's rock, I've noticed the number of covers done by Zep, George Thorogood, Foghat, etc. I decided I wanted to find out what what the originals sounded like, and so starting to explore the blues. I've dug in to some of the early stuff and listened to Howlin' Wolf, Otis Rush, Bo Diddley, Muddy Waters, Little Walter, Willie Dixon, Koko Taylor, Amos Milburn, among others.

Very recently however, I've been exposed to Hot Tuna, Johnny Winter, Pat Travers, UFO, Robin Trower. I've found that I really like what I've heard by all these fellows. (But I distinctly do not like Stevie Ray Vaughn) My first question is, are the latter three considered blues? Second question is, can anyone with similar tastes recommend other groups I might want to look into?