Leonard Cohen, Patti Smith.
I live in a cultural backwater (not really).
All before induction:
The Grateful Dead
Don Henley (ex-Eagles)
Santana
Billy Joel
Bruce Springsteen
Tom Petty
Buddy Guy
Pretenders
U2 (twice)
Ozzy Osbourne (ex-Sabbath, at least twice…hazy memory from those days)
Sammy Hagar (pre-Van Halen)
Metallica (5x)
Genesis
Rush (3x)
Peter Gabriel (2x)
Could have seen Pink Floyd and Nirvana but changed plans at the last minute.
Hon. mention: Roy Orbison, never saw him perform but I met his family shortly before he died.
Bob Dylan
The Rolling Stones
Booker T. & the M.G.'s (together with Neil Young)
Van Morrison
Neil Young
David Bowie
Pink Floyd
Santana
Eric Clapton
The Police
ZZ Top
U2
R.E.M.
Guns N’ Roses
I didn’t even look beyond the “Performers” list. I can add Bill Monroe and Chet Atkins as well.
The Ramones.
Black Sabbath.
Eric Clapton.
I just plain missed seeing Chet’s name! I’d add him in a heartbeat.
I have some more to add- Carl Perkins, Jackson Browne and (as a solo act) Lou Reed. They were all at Farm Aid 1990 in Indianapolis. That concert was ridiculous; there were around 70 acts, in one day, on one stage. Most of them did maybe two songs and left the stage. I can’t remember everyone who was there. Bonnie Raitt, Neil Young and CSN were there but I saw them all before Farm Aid as well.
Anyway, here’s my revised list:
Bo Diddley*
BB King*
Carl Perkins**
The Beach Boys
Bob Dylan & The Band (1974, the Before The Flood tour)
Bobby “Blue” Bland
Elton John**
The Allman Brothers
Neil Young
Pink Floyd
Crosby, Stills & Nash (with Neil Young)
The Eagles** (most of them anyway, doing an acoustic set at Farm Aid)
Santana
Paul McCartney
Eric Clapton
Bonnie Raitt
Jackson Browne**
Buddy Guy
John Mellencamp**
Iggy Pop & The Stooges**
Neil Diamond
Guns ‘N’ Roses**
Bill Monroe**
Chet Atkins
As solo acts-
Ringo Starr
Roger McGuinn
John Fogerty
Ernie Isley
Robert Plant
Lou Reed**
*After induction
**At Farm Aid 1990
.
Well make it snappy. We aren’t getting any younger.
Jackie Wilson
The Rolling Stones
The Four Seasons
Van Morrison
Talking Heads
Elvis Costello & the Attractions
ZZ Top
Little Anthony and the Imperials
Dr. John
Tom Waits
Albert King
Hmmm… Looks like I’m the only one to have seen Jackie Wilson. 
Yeah I had heard that, but my impression after meeting him and talking with him was that it isn’t true, at least not in an absolute sense. Lemme tell ya my story:
The club I was working in at the time was a converted Winn-Dixie supermarket building. It still had the sort of half-dock at the back of the building, which was also backstage, so of course that’s how we loaded acts in. Well, MoR were playing with someone else that night, I think it might have been Living Colour. Anyway, we had finished loading the bands in and done soundchecks, which meant that everyone left except me. I stayed to focus my lights and build some presets. Once I was done with that, I had a few hours before show, so of course I went into our little stage office and rolled a joint.
I remember it was a nice day, not too hot, and of course I went out onto the loading dock to smoke my joint (we didn’t smoke in the club, natch). So I go out there and spark up as I walk thru the doorway. Sitting on the dock there’s this guy: older, skinny, shirtless, wearing a pair of shorts and some cheap sneakers with no socks, smoking a cigarette and handling some drum heads. I watch him take a puff on his cig and then use the cig to semi-melt the drum heads, pulling the more severe dings out. I hadn’t met him on the load in, but I its not uncommon for a roadie to sleep in during load in and only get up when he’s actually needed, so it wasn’t crazy strange to see this guy.
Anyway, I said howdy and asked him if he wanted a hit off my joint and and he’s like “nah mate i’m fine with my fags”. The accent is unmistakably British, and as he raises his head to see me I in turn see his face and realize “holy fuck Ginger Baker is sitting on my loading dock!” Then I realize “holy fuck Ginger Baker is sitting on my loading dock REPAIRING HIS OWN DRUM HEADS WITH A FUCKING CIGARETTE!”
So of course I say to him “holy fuck you’re Ginger Baker!” and he’s like “yup that’s me” and I go “what the fuck are you doing?” and he’s like “ah its an old habit and they’re still good heads, so ya know it gives me something to do.”
“But dude,” I said, “you’re Ginger fucking Baker! Dude, I can get you some drum heads! I could call any of 3 or 4 people and have a new set of heads here for you in like 30 minutes.”
“Nah, that’s alright, I’m almost done now” he says.
So he finished fixing his heads maybe 10 minutes later, asked me for the joint and we sat and shot the shit for an hour or so while we ate and drank from the band’s catering spread. After an hour or so I rolled another joint; we ended up still sitting on the dock chatting until the bands and road guys started showing up, then he went and put his drum heads on his kit and did a quick soundcheck to make sure they felt and sounded ok, then he went off to shower and prolly get in a short nap before the show.
I remember talking about the band he was playing with quite a lot; he really liked the guys and was quite impressed and enthusiastic about their music. He had been having an okay time on tour but not a fantastic time, although he said some shows were terrific while most were just good-to-really-good.
In my experience he was a very smart, somewhat reserved guy with a very wry & dry sense of humor. I found him easy to talk with and very down-to-earth. He was knowledgable on, and had opinions on, a wide range of subjects so our conversation meandered from this to that to some other thing. I found our conversation entertaining and engaging.
The other guys I worked with were shocked that I had not just met him but had talked with (and smoked pot with) Ginger Baker; they didn’t know he was playing with MoR at all since none of them even knew of the band before the show got booked. I remember I had to find a copy of the Friday entertainment section of the newspaper from the week before to show them that Ginger Baker was in fact the guy who was going to be playing the drums that night. My friend Dennis was pissed for weeks that he missed a chance to meet Ginger Baker and get high with him :p.
While I working at the same club I had similar experiences with Meat Loaf (who I didn’t even recognize because he was fairly skinny and had cut his hair off; after a 30 minute convo someone called to him “Meat we’re ready for ya” and he tells me “ok, I gotta go they’re ready for me” and I’m like “sure thing man break a leg” but until then he was just some guy I was talking basketball with.
Also used to do a lot of shows with the Neville Brothers, and I can say that Charlie and Aaron are two of the nicest guys you could ever want to meet. Super musicians and super people.
The Beach Boys (80’s version with John Stamos)
The Rolling Stones (1998)
Santana (1998, opening for the Stones)
AC/DC (first in 1985)
ZZ Top (1987ish)
Black Sabbath (1995 with Tony Martin, 2007 if you count Heaven and Hell with Dio, and 2013 with Ozzy)
Van Halen (1984 with Dave and 1986 with Sammy)
Metallica (1995 opening for Motörhead)
KISS (various times since 1979)
How the hell is Deep Purple not in?
Adding another one: Etta James
Only Alice Cooper. And not even specifically, s/he was opening for Motorhead in 2011.
Janis Joplin, long before…
James Brown
Aerosmith
Ramones
KISS
Elvis Costello
You saw Alice and you don’t know what sex Alice is?"
Forgot to add Elvis Costello. (before)
All very cool - thank you for the inside scoop, Bo. Sounds like Ginger saves his irascibility for the press and perhaps some of the musicians he’s worked with 
More than I expected:
BB King
Stevie Wonder
Booker T & the MG’s
David Bowie
Paul McCartney
Tom Petty & the Heartbreakers
Elvis Costello
U2
REM
Patti Smith
The Ventures
The Stooges
Dr. John
Red Hot Chili Peppers