Oh, so many, including many listed here already.
I’ll add all the Gerry Anderson shows, Death in Paradise, My Family, My Hero, Absolutely Fabulous, As Time Goes By, Waiting for God, Murder, She Wrote, Through the Decades, New Tricks, Blackadder I-IV, VisionOn, Paulus the Little Gnome, The Banana Splits, Bewitched, The Carol Burnett Show, many many Looney Tunes/Merrie Melodies and the like, and Land of the Lost. Probably lots of others. Dangermouse. BtVS and Angel. My Favorite Martian.
Oo! Series like Connections and Connections 2, and Cosmos (both).
I’d want to add B5, but when you get down to it, that is rarely what I’d call “comfort TV”.
And I’d better post this before I add about another eleventy-million choices.