There are those I haven't seen, noted earlier. But I'm happy that I HAVE seen The Chad Mitchell Trio with John Denver, Judy Collins, the Clancys in the early '80s, Tommy Makem, the Makem Brothers, PP&M, The Highwaymen,
Natalie Macmaster, and The Celtic Fiddlers (to name a few). There is some value in being older and blessed (or cursed) with a very good memory -- I can relive concerts.