Dictionaries of abbreviations
Related to: Dictionaries, Palaeography, Abbreviation
Probably the most famous one is Adriano Cappelli – Lexicon abbreviaturarum:
https://scrapbox.io/files/62161ac5bc8c9200232edcbd.png
There are many editions of it in different languages: http://classica-mediaevalia.pl/2012/10/adriano-cappelli-lexicon-abbreviaturarum/ . There is also a recent free online version: https://www.adfontes.uzh.ch/ressourcen/abkuerzungen/cappelli-online/characters/up/1
Dictionaries of abbreviations
A bunch of older dictionaries as PDFs collected by myself:
Varia lexica abbreviaturarum.pdf
MARTIN - The record interpreter: a collection of abbreviations, Latin words and names used in English historical manuscripts and records
https://archive.org/details/recordinterprete00martiala/page/n4
⭐️ AbbreviationesTM Online (paywall 💵)
URL: http://www.ruhr-uni-bochum.de/philosophy/projects/abbreviationes/index.html
Unpuzzling abbreviations
⭐️ Enigma: Unpuzzling difficult Latin readings in medieval manuscripts