Beatles once, August 1965. Since the screaming audience was “only” 17,000+ I could hear the music just fine.
Doors, with Jim Morrison four times: 10-67; 6-68; 12-68; 8-70;
Doors, after Jim 8-72 (Full Circle tour)
Virgil Fox three times, all in the early 70’s
Frank Zappa four times: 3-73, 8-74 (conducting orchestra), 9-75, 12-75
ELP three times: 2-74 (Brain Salad Surgery Tour), 8-77 (Pirates tour), 8-77 (four days later, different city)
Ha! That’s what I tell myself every. single. time. at Gwar shows. “I’ll just hang back this time” or “I’m too old to be crushed at the front” or “I don’t need to hike down Sunset strip soaked in gwar blood anymore”. But as soon as they start, I start giggling like a Japanese school girl and start making my way up front.
I think I’ve seen Patti Smith 4 times.
I think I’m up to 6 times each for Wilco and Hold Steady.
I also saw Queensryche on the Empire tour w/ Warrior Soul, then again for Promised Land. I hope to see their current lineup this year sometime.
I’ve seen Weird Al 6 times in two countries; Okkervil River 5 times (twice in one day in Chicago); Gillian Welch three times; Santana twice.
I’ve seen Weird Al twice; both times in Merrillville, Indiana (of all places). He did a “meet and greet” after one of them, so a friend and I were able to talk to him for a few seconds. Super nice guy.
The Eagles 3x. I guess that’ll be it for me since Glenn Frey up and died on me last year. (However, on June 15th, I’ll be seeing Don Henley.)
Journey 2x, once with Steve Perry and once with Arnel Pineda. The former was about 10x bigger and badder, but the latter was sweetly reminiscent. Somehow I missed Steve Perry when he was doing his solo tours in the 90’s. I guess I was busy being a Mom.
Elton John 2x. His voice is suffering but he can still bang out some tunes.
BeeGees 2x. My ears are still ringing, and that was 1979.
Prince 1x. 3 years ago, I searched his website for live performances and was actually considering flying to LA to see him, since he so rarely performed. I didn’t and now really regret it since he, too, died during the Black Death Plague of 2016. 
Elvis 0.
Billy Joel, who I’ve seen twice, is the same way.
They’re playing a couple of shows this July as the Eagles w/ Glenn’s son Deacon Frey.
Jeez, guess I don’t get out much…
College, in the 70s:
Tull 5X, including the Passion Play show that Nick Kent savaged
Yes, 4X, including being an opener for one of Tull’s shows on the Aqualung tour.
Firesign Theatre, only 2X, A Roxy show and Royce Hall show
Residents, 2X, Cube E and Mole Show
Dan Hicks in various band configurations, 4X
Drops off after that.
X, a few times around clubs in LA, 80s.
Diego’s Umbrella, six or seven times, although I prefer their middle stuff when The Token Ecuadorean played with them
Grateful Dead 87 shows w/Jerry including the last 6…should haave been 7, Fence Jumpers SUCK!
RatDog 20+/-
Leftover Salmon 20+/- plus a night roaming around with them in Carbondale IL playing house parties and other nefarious things…
and entering the way way back machine…“Ken Carlisle and the Cadillac Cowboys” 50+/- I was an amateur rodie/photographer for them.
Rush: Every tour that came to the area between Grace Under Pressure and the farewell tour (a couple times twice for the same tour, during the outdoor and indoor legs). So…I dunno, maybe 10?
Alan Parsons Live Project: 3 or 4, including once when they opened for Yes and the tickets had the wrong time so we missed most of their set, but when Alan found out (the tickets were part of a fan club thing) he got the fan club group (6-8 people) refunds and we got to go backstage and hang out with the band during all of Yes’s set. Alan Parsons is an awesome, classy guy. 
Alice Cooper: 3 (including one VIP experience thing where we got to hang out with him backstage briefly)
VNV Nation: 2
Peter Gabriel: 2
In looking back at my ticket stubs from the 90s I see that Harry Connick Jr was graced w/ my presence on the lawn at 3 concerts; 2 in his Tony Bennet-esque years and again when he went heavier Jazz w/ She. He puts on a hell of a show.
Wherein, I assume, you were educated on the etymology of the name of the city?
Haha! No - he didn’t tell us what “Stockton” meant. 
(And we didn’t say “We’re not worthy!”, figuring he probably heard that one every night.) He did spend more time discussing theology with the spouse than he did talking to me, though, and it was supposed to be my birthday present.
He signed my steampunk leather top hat, though, so it was all good.
Van Morrison…5 or 6 times, some of which were actually longer than an hour and he was in a good mood. All of them worth it nonetheless.