One of my favorite Youtube channels I've come across in the last year is BBC Archive. Not fiction, but a mix of documentaries, interviews, human interest stories, and educational content from the 50's to the 80's and a little bit of 90's. This 1970 short film on a Scottish boy's last carefree days before starting school is probably my favorite that I've seen so far.
https://www.youtube.com/watch?v=Kv6PJd6ZvHY