This list is not complete because it's updated manually, so if you don't find what you are looking for, double check in the search bar in the upper right side of the page.
This list is systematized under special historical periods (Renaissance, Baroque, Classical, Romantic, and early 20th century) and national schools and each composer is arranged alphabetically. When downloading the scores please observe if the work is in public domain in your country and what kind of licence is granted for the use of this work (some modern editions allow only non-commercial use of their scores so it's always good to check that).
I think this list is a real treasure not only for organists who are looking to expand their concert and/or liturgical repertoire but also for people who enjoy playing organ at home for their own pleasure only.
Of course, printed and copied music does not have any long-term value and may quickly deteriorate and nothing can change the wonderful feeling of holding a real book or collection of music compositions in your hands.
However, for a quick everyday use you will not easily find a better place. In fact, the list is quite large and extensive and one can get easily lost while scrolling through pages and pages of music. In a sense it's a wonderful education in itself available for us just one click away.
By the way, do you want to learn my special powerful techniques which help me to master any piece of organ music up to 10 times faster? If so, download my video Organ Practice Guide.