OK ... I'm gonna suggest Sonny Boy Williamson stuff ... Howlin Wolf ... early BB and Albert KIng ... and the ever popular Elmore James ... I kinda think that's what we are talking about here ... could be wrong
When you play blues remember it's a feel thing ... but to make it sound right there is actually a lot of technique involved. The mistake to many people make is thinking it's too easy.
First ... learn the number system ie: the 1 is the root note ... in the case of playing in the key of A it's usually the fifth fret low E ... therefore your chord changes on a 3 cord blues are a 1,4,5 ... A,D,E . Now lets say you have singer sit in, that sings a song your used to playing in A to say G, easy just move to the G as a root and go with it ... the 1/4/5 stays the same.
Now moving past the basics you need to remember certain rules apply ... "Always lock in to the ONE" and emphasize that note ... THIS does NOT mean only the 1 in the chord progression but the dominate root note of each beat cycle (locked with the kick drum ) on the 4 and 5 changs etc:
Now lets kill off the next myth ... NOT all blues is the same thing over and over. Many blues songs have "short 4" it means the 4 is played twice, once before going into the 4/5 turn-a-round ... the T Bone Walker classic "Stormy Moday" is a good example of this ... BTW it also slides to a "sharp 5" on the turn-a-round. You may also start a song on the 5 ... basicly starting at the 5 to the 4 and into the progression.
Know also that there are many types of "patterns" a singer may call ... shuffle, slow blues and box ... even a hold on the ONE and "vamp" until they are ready to start or re-start the progression (a lot of harp players do this)
I'm only scratching the surface here ... there is so much more ... learning to play "behind" the beat, and the 2/5 change the 1/6/2/5 turn-a-round ... and the walking techniques using interchangable 3rds ... etc:
It's cool

stuff once ya get it.

... Wait a minute, someone mentioned Texas and Chicago blues ... it was here FIRST! ... still is.