I’ve looked just recently for a listing of top TV themes ...by actual charting.
Not so easy to find actual chart-topper lists. It’s mostly opinion which is totally bogus and useless most of the time.
As for some of my favorites...
Welcome Back Kotter (thanks for the reminder commercial)
Happy Days
Come on get Happy (cannot BELIEVE this didn’t chart)
Oh yeah, I thought about this one too! Partridge Family was great -- and lots of good songs from the show, too, not just the theme. Full disclosure: I was born in 1967