Lots of good ones such as King Crimson in 1972, Hawkwind (three times), Captain Beefheart, too many to mention at festivals like Knebworth and Reading. But one that was memorable for a different reason - I went to see Santana and was really looking forward to it. The support band was Earth, Wind & Fire, whose music wasn't my cup o' tea at the time and I thought they were a surprising choice. Wow! They were fantastic... what a set, and the place was buzzing. After that, Santana were a bit of an anticlimax.
Later good gigs have been the Rolling Stones in Paris, AC/DC in various places, Bon Jovi at Wembley.
I'm sorry I never got to see Prince.
The last gig, and highly enjoyable, was a little known German band called Double Crush Syndrome. My son and I had a cracking night and I'd go and see them again tomorrow. Oh, and a band called Hayseed Dixie. Seen them a few times too. I hope 2021 brings more concert opportunities.