For example, want to see what's in a Medieval Bestiary? Here's one site that is an amalgamation of different manuscripts, with the pertinent information, in this site's case, translated into English. You can see a gallery of images, which manuscripts mention which animals, etc. So, you can read up on creatures you've probably never heard of, like Amphisbaena and Parandrus or supposedly common creatures, like pelicans and salamanders.
|Pelican - Museum Meermanno, MMW, 10 B 25, Folio 32r|
Or this site, also from the Morgon Library, that allows you to scroll through one manuscript, the Black Hours (Belgium, Bruges, c. 1470 (MS M.493), a Book of Hours written and illuminated in silver and gold on parchment that was stained or painted black.
|"Black Hours," for Rome use. Belgium, Bruges, c. 1470 (MS M.493).|