Knights Templar playing chess, Libro de Ajedrez, dados y tables, Alfonso X, 1283. Used under Creative Commons license.
Internet Medieval Sourcebook - full text sources from the Crusades, etc. translated from Fordham University
Epistolae: Medieval Women's Letters - letters to and from women, 4th-13th century AD, in translation, by Dr. Joan Ferrante.
Labyrinth: Resources for Medieval Studies - collection of primary sources in translation from Georgetown University
EuroDocs - search by country, then scroll through the chronologically-arrange primary sources. Not everything is in translation.
Crusade Texts in Translation - both European and Muslim perspectives in many separate ebooks volumes
British Library Digitized Manuscripts - A major collection of digitized manuscripts. Use this website to view digitised copies of manuscripts and archives in the British Library’s collections, with descriptions of their contents.
Digital Bodleian - Major collection of Eastern and Western manuscripts available online.
For much more precise, relevant results, try the following instead of SuperSearch: