https://archive.org/details/classic_tv
http://www.tvland.com/full-episodes
http://www.youtube.com/channel/SBpcHF0FYOb_k (Fawlty Towers!)
http://www.fiftiesweb.com/tv-shows.htm (beware pop up ads)
http://www.nbc.com/classic-tv/
Thanks for the links. Some I already had (I’ve nearly memorized the Fawlty Towers episodes :-). I expect to find other shows I like, though, in the links I haven’t checked yet.