Here is a list of digital primary source collections that contain free transcriptions or etexts that are easily accessible for personal use.
EuroDocs: This compendium of European primary sources contains links to transcribed, translated, or facsimile-reproduced sources. EuroDocs was created by Richard Hacken, European Studies Bibliographer at Brigham Young University. The database is searchable by country or time period.
European History Primary Sources: A website with hundreds of links to primary sources based on European history. It contains a listing of numerous digital repositories and is searchable by language, country, and time period. I’ve only delved a little into the EHPS, but it is quite phenomenal. EHPS is managed by the Department of History and Civilization and the Library at the European University Institute.