The Eel-Rents Project is a multimedia platform for an exploration of eels as a part of the economy and culture of eleventh-century Britain. The project presents an interactive map that shows the location of eel rents in the Domesday Books and also presents a bibliography and discussion of the importance of the aquatic animals to early English life.
Archives
Medieval Bestiary
This web site deals with any and all aspects of the general topic “animals in the Middle Ages”, though there is an emphasis on the manuscript tradition, particularly of the bestiaries, and mostly in western Europe. The subject is vast, so this a large site, with well over 3000 pages, and perhaps the best way to explore it is to just wander around. The various pages making up the site are extensively linked; any text appearing in this blue color is a link (except for that one!). You can also click the green arrows at the top and bottom of each page; these will take you from one section to the next, or to the next page in a series. If you get lost, click the 
button on any page to return to the table of contents. If you are interested in bestiary manuscripts, start wil the section on the manuscript families, which will link you to various other pages of interest. If you want to learn about a particular animal, start with the Beasts pages. If you are looking for something in particular, try the site search. For more help in navigating the site, click the green 
on any page.
Informal articles, opinionated reviews, and irreverent comments on the bestiary genre can be found in the bestiary blog, Chimaera.
(Please note: this resource has not been updated since 2011, including the bibliography)
PhiloBiblon
PhiloBiblon is a free internet-based bio-bibliographical database of texts written in the various Romance vernaculars of the Iberian Peninsula during the Middle Ages and the Early Modern period. It includes the primary sources of those texts, both manuscript and printed, the individuals involved with the production and transmission of those sources and texts, and the libraries holding them, along with relevant secondary references and authority files for persons, places, and institutions.
Notes from reviewer:
PhiloBiblon combines a search of four online bibliographies of the Iberian Peninsula during the Middle Ages. As noted on the site, “There has been little concerted attempt to coordinate data among the four teams. Discrepancies will be found, for example, in the titles of texts originally written in Latin and in the names of individuals. In the case of translations from one Iberian language into another, however, the team describing the translated text tends to defer to the expertise of the team dealing with the original. There has been no systematic attempt to copy all of the information from the authority files of one bibliography into those of another.” This may make the resource confusing for inexperienced users.