Everly Brothers
Beach Boys
Bob Dylan
Dion
Kinks
Simon & Garfunkel
Duane Eddy
Carl Perkins
Tom Petty & the Heartbreakers
Hall & Oates
The Ink Spots
Bill Monroe
Chet Atkins
Oh, thanks. I knew him as John Cougar Mellonballs.
Just noticed the Grateful Dead was on the list. I can add Phil Lesh to my list. I saw him years ago when Phil Lesh & Friends opened up for The Allman Brothers. I swear, at one point, there must have been at least 10-15 people on stage.
While I was (and am) familiar with The Dead as band, I certainly don’t know all the ins and outs of them. I’d like to think that I saw either Bob Weir and/or Derek Trucks at that show. This would have been sometime around 98-02, couldn’t tell you when for sure, but I’m quite sure I wouldn’t have recognized Derek at that point. I remember seeing him on TV a lot (playing) and always thinking he looked just like that girl I went to grade school with. It was an embarrassingly long time of seeing him on different shows before I even knew he wasn’t a girl (remember, he doesn’t sing and usually has his head down).
I missed one: Bo Diddley (after induction)
He was on there? Add him to my list as well. He opened up for Tom Petty one year (as did Steve Winwood another year).
Yep, inducted in 1987.
Little Richard (after)
BB King (after)
Tina Turner (solo-before)
Santana (before)
Ramones (before)
U2 (before)
R.E.M. (before)
Run-D.M.C. (before)
Iggy Pop (solo-before)
Rush (before)
Yup. A lot of people must have expecting the Go-Go’s in Tucson (where I saw the Police play) judging from the number of women who were dressed like Belinda Carlisle.
One technicality: I saw Dave Davies of the Kinks perform this summer. It was a pretty pathetic spectacle; his singing was no better than some drunk bozo at karaoke night, so I don’t count this performance as qualifying for the OP’s question.
Missed Buddy Guy
If we count members of bands appearing in other bands and as solo, I can add
John Sebastian (solo)
Chris Hillman of the Byrds (as part of the Flying Burrito Brothers)
Richie Furay of Buffalo Springfield (as part of Poco)
Quite a few more than I would have guessed, it turns out:
Muddy Waters
The Beach Boys
The Who
Rod Stewart
Paul McCartney
Bruce Springsteen
AC/DC
Elvis Costello
Bob Seger
ZZ Top
Lynyrd Skynyrd
Neil Diamond
Kiss
mmm
Alice Cooper nine times between '77 and Nov 2013.
the Rolling Stones in '89
Chuck Berry*
Ray Charles*
B.B. King*
The Drifters
The Temptations
Stevie Wonder*
Four Tops
John Lee Hooker
Booker T. & the M.G.'s
The Isley Brothers*
Elton John*
Rod Stewart*
Parliament-Funkadelic
Santana*
Billy Joel*
Bonnie Raitt*
James Taylor*
Aerosmith*
Ramones*
AC/DC
Prince
ZZ Top
Buddy Guy
The O’Jays
Little Anthony and The Imperials*
Metallica*
Beastie Boys
Red Hot Chili Peppers*
Heart*
Randy Newman*
Public Enemy
Peter Gabriel*
Hall & Oates*
KISS
Linda Ronstadt*
And although I never saw Cream, I did spend a terrific couple of hours smoking pot and shooting the shit with Ginger Baker one afternoon while he was touring with Masters of Reality. He’s a really, really cool guy.
ETA: Oh yeah, the * is for an artist that I was working for when I saw them. A lot of those acts I saw when I was young as a fan and later ended up working their show as a local hand or having them play a gig I had set up (a festival, trade show, etc.). Either way, at least once, I got paid to see those acts.
I’ll play
Simon & Garfunkel (before)
Billy Joel (before and after)
Elton John (can’t remember-I think both before and after)
I attend woefully few concerts
I’ve just seen Rush, twice (2004, 2008) before their induction.
Angus Young wears an Ashfield Boys High School uniform. I see kids going there every day. Surely that counts - they’re about the same height and everything.
Wow, Jonathan Chance, TreacherousCretin, and Snowboarder Bo. You three deserve some sort of Hall of Fame of your own!
All before:
U2
Kiss
Pink Floyd
The Ventures
Metallica
Red Hot Chili Peppers
Guns n Roses
Public Enemy
ZZ Top
Also Iggy Pop solo and John Lydon with PIL.
Almost saw Nirvana, but I just saw Mudhoney and couldn’t afford two shows in one week. If I had gone I would have seen an acquaintance of mine punch Kurt Cobain in the face onstage.
When friends were being snarky in high school it was John Cougar Menstrualcramp…
…hey, it was high school. 
Snowboarder Bo - Your comment that Ginger Baker was a “very cool guy to hang with” is pretty much the ONLY positive comment I have ever heard about Ginger that wasn’t focused on his drumming ;). Seriously, his rep is that he is a huge antisocial prick - I am sure you know his rep, too - what can you tell us that’s different?
As for the question in the OP - I am sure it isn’t many for me. Stones, Beck, Clapton, Gabriel, Bruce, a few others. Concerts are typically tough for me - the queuing up, the waiting, the crowds, the waiting to leave, etc. - too much potential for hassle and stress with a lot of potential for a meh show. Totally my issue.
Thought I was going to have a unique pick with Bill Monroe until I saw Sigmagirl’s post.
Buddy Guy
Paul McCartney
James Taylor
Chris Hillman is two different non-Byrds groups. John Paul Jones in a non-Led Zeppelin group.
I think Hal Blaine was on drums when I saw John Denver.