I. Medieval Latin Tools
Adriano Cappelli’s classic introduction to Medieval Latin Paleography translated by David Heimann and Richard Kay.
This is an online version of Adriano Cappelli’s Dictionary of Abbreviated Latin Words (1928 edition).
An online Latin dictionary and grammar tool developed by William Whitaker and housed at the University of Notre Dame.
Abbreviationes is an online tool for de-coding medieval Latin abbreviations (developed by Olaf Pluta).
Enigma is an online tool for deciphering abbreviated Latin words. The search tools allow for the implementation of “wildcards” into your best guess and searches the possible Latin words.
II. Library Tools (to find incunabula or early modern printings)
This is the first place I begin a search. The search options are easily fine tuned and the interface is great. (There are also loads of great texts).
Despite the name, this database (begun by David Sytsma) has an enormous amount of medieval texts. A great place to find early modern printings.
An excellent library search engine that spans numerous countries and libraries.