Oldtimer looking for Anime soundtracks

This is my first post here, I'm an amine old schooler (Anything from
early 70s to mid 80s, so I know what a record album is). But I'm
looking for places online that have CDs for music from those years.
I'm especally into the themes, op and end. Giant robots, sci-fi, some
comedy. Any help would be appreciated

Jim