Hi! I'm a writer that's attempting to write a book about lesbians that takes place in the 1950's. As a result, I've done a good bit of research on lesbian history.
For some interesting/lighter reading, Autostraddle has a series of articles about lesbians in history. Here's a link to them.
This website has some pretty interesting stuff about queer women in history, too.
I've enjoyed reading both Boots of Leather, Slippers of Gold by Elizabeth Lapovsky Kennedy and Madeline Davis and Odd Girls and Twilight Lovers by Lillian Faderman. They're both very informative, and I like them because they both have pictures and commentary from lesbians that actually lived during the periods they talk about. Both of these books can be fairly expensive if you're trying to buy them, so I suggest checking out digital copies of them for free on openlibrary.org.
I don't know if you're interested in historical fiction, but if you are you HAVE to read Stone Butch Blues by Leslie Feinberg. It's not the most elegantly written book, but damn will it tear you apart. It also gives you a great perspective on queer women's culture in the 60's and 70's.
There's also Fried Green Tomatoes at the Whistlestop Cafe, which is both a book and a movie. I find the movie to be disappointing because the lesbian relationship from the book is just turned into a "special friendship" but it's still pretty good if you ignore that part.
As for films, I don't have any nonfiction, but some great historical fiction movies with lesbians in them are If These Walls Could Talk 2 (this one is all about lesbians) and Common Ground (a third of this one is about lesbians. But it's a pretty enjoyable third.) The BBC also did a miniseries called Tipping the Velvet, which is based on a book by Sarah Waters. You can find all of these for free on Youtube.
I mostly know about the 1950's, but I know a bit about the 60's as well. Here are some things you might want to research:
50's: working class butch femme bar culture, lesbian pulp fiction, Cherry Grove, the Daughters of Bilitis, and the class and racial divides amongst lesbians during this time
60's: Second wave feminism's affect on lesbianism, the Lavender Menace, Rita May Brown (and her book Rubyfruit Jungle), and the Stonewall riots
Hope I could help! :)