Check out some of the rare films released on the Criterion sub-brand Eclipse. There are over 40 (DVD only) boxsets of some more obscure directors and unknown films from all over the world. Some of my favorite sets are the Czech New Wave, Late Ozu, Early Bergman, Larisa Shepitko, Hiroshi Shimizu, Chantal Akerman, and many others. There is also the World Cinema Project of boxsets (3 currently) with multiple films in each set, restored by Martin Scorsese and also released by Criterion. These are unknown films from non-Western countries (mostly) that should be watched by more people who love film.

Here's a thorough list of all the Criterion boxsets. You could learn much from viewing many of these -

https://en.wikipedia.org/wiki/List_of_Criterion_Collection_boxed_sets