A few notes:
1) Films missing are mainly hardcore porn and TV shows (Hitchcock mysteries namely). There's a number of others missing as well from Letterboxd. I have a small list I'll be adding to TMDB so hopefully this can be rectified overtime.
2) Leave a comment if you notice a film missing from this list that's on Letterboxd, I'll add. Same goes for if a film is on here but no longer (or never was) available on Rarelust.
3) I'll try to keep this updated. (Current to Rarelust January 9th, 2021 Update)
4) Letterboxd can only show a max of 128 pages of results or 12,000 films (despite having no limit to list size). This list has a little over 14,000 films so you need to filter to find things.
5) All credit to Rarelust.com for providing a much needed service archiving and providing these films.