On a related note, Mosfilm has a Youtube channel with high quality version of many of their films, including most Tarkovsky. The channels is all in Russian but English sub are typically available, and search works in English too.
With regards to copyrights, it seems all films released after 1973 are covered by it, however the laws between ex-Soviet countries differ. Sources:
I would encourage people to use legal means to watch these movies, especially in Europe where many of them have been re-published legally with English subs, often by small/indie companies.
The other day I watched "White Sun of the Desert", and found it excellent: https://www.imdb.com/title/tt0066565/ - very much reminded me of the Dollars trilogy.
(recommendation from Chris Hadfield, of all people; apparently this film is traditional to watch the night before Soyuz launches)
"Mosfilm" is a good search term and for more lighter and fun content is "Soyuzmultfilm", which is kind of the Russian Disney. Especially the older children series like Cheburashka are interesting and contemporary Masha and the Bear is immensely popular.
[1] itself a reference to a folk tale, while "immensely popular" means Masha has even been a guest on the same late night talk show frequented by better US ambassadors.
https://www.youtube.com/watch?v=nmcHXt1va_c
[2] just in case any americans are curious about what what parts of their culture make it across the Bering strait.
"American Boy" (1991), a song by a late-soviet pop group, may also be of interest: https://www.youtube.com/watch?v=W7hAo28NCXc (Apina and Varum have gone on to lasting fame)
With regards to copyrights, it seems all films released after 1973 are covered by it, however the laws between ex-Soviet countries differ. Sources:
http://www.kirj.ee/public/trames_pdf/2014/issue_3/Trames-201...
https://en.wikipedia.org/wiki/Copyright_law_of_the_Soviet_Un...
I would encourage people to use legal means to watch these movies, especially in Europe where many of them have been re-published legally with English subs, often by small/indie companies.