From the 80s and my student days
Joe Jackson doing his "Jumping Jive" tour of swing era music. I'm a big admirer of Jackson and each albums and tours are generally an exploration of a totally different style
Misty in Roots - live at the counter-vision tour. A London based roots reggae band. The album of the tour is still one of my favourites some 40+ years later. Sadly their current tour of the same material which I had tickets for has been postponed so hopefully will be re-arranged
Yessir - a rhythm and blues band (in the old bluesey meaning). Never heard of them before or since but they played their hearts out to a tiny audience which they almost outnumbered. They started off well so we cheered and applauded extra enthusiastically to make up for the low turn out, and they just got better and better. It was a real privilege to be there.
In more recent years
King Crimson in Cardiff a couple of years back with mostly the original line up back with the band. No light show, no "hello Cardiff!" shouting, just incredible playing of complex music with a polite bow at the end of each number, and bandleader Robert Fripp sitting quietly at the back playing his guitar. But what a gig!
And again in the last few years Black Sabbath in, I think, their last but one tour. Perhaps the only stadium sized gig I've been to and genuinely enjoyed. Ozzy was clearly far from in his prime by this time, but he clearly loved entertaining the crowd and his joy in performing his old hits once again really was rather special. He was still a superb showman and it was a great gig.
Recently, The Ruts, at a relatively small venue in Bristol. Three oldish chaps who sat down to play, and notably their drummer only had a base drum, snare drum and high hat, but it was one of the tightest bits of drum playing I've heard. Played all their old hits like Babylon is Burning, in an exceptionally good gig.
I'll maybe do another list of exceptional classic gigs over the years.