A lot of the popular Anime from back in the days or ongoing series that first started way back, that many people in their early 20's or older will connect with or have fond memories of. To expand the list a bit further, Anime...
Estimated chronological order of the various Slayers anime, as seen here: http://www.anime-now.com/entry/2017/02/19/000050 (This is basically a recreation of that list in a place where I can get to it easily, lol)