As the 1762 archive project works towards fully annotating selected texts in the corpus, we have been using the following research aids for transcribing and translating 16-18th c. Spanish texts.
This amazing online tool is the best out there. It lists common words that are abbreviated in official Spanish documents and gives their full text equivalents.
And it is free and available online!
Diccionario de abreviaturas novohispanas
Diccionario de Autoridades
A good historical dictionary of the Spanish lexicon used over time is essential for identifying words and getting at their precise meanings. The Diccionario de Autoridades , the first lexicographical compilation of Spanish with examples from different historical periods is now available online. You can even look for meanings of common phrases.
The online tool may be accessed here
Diccionario de filipinismos con la revisión de lo que al respecto lleva publicado la Real academia española
Compiled by Spanish historian and bibliographer Wenceslao Retana (1862- 1924) ,the Dictionary was published in 1921.
Retana, said to be the "onetime adversary" of Philippine national hero José Rizal" later became an "admirer" who wrote the first biographical account of the life of Rizal entitled Vida y Escritos del Dr. José Rizal or "Life and Writings of Dr. José Rizal". Rosa M. Vallejo described Retana as the "foremost" non-Filipino filipinologist. The Dictionario de Filipinismos was a product of Filipinismo as an area of study - an early version of Philippine Studies done by non-Filipinos.. Retana's Dictionario compiles words or phrases with specific and often different meanings in the Philippines, or in the Philippine language.
There are several editions of the book, but the 1921 edition is freely available and searchable online here.