The Old Frisian corpus comprises diplomatic editions of the main Old Frisian manuscripts. These texts are fully searchable by word or wordform and results are shown in context. The 'list text' option shows which texts are included for each part of the database. To search the Old Frisian corpus in its entirity, go to 'Databases 1300-1800' and select 'tdb_Aldfrysk'. Put in a search term, having checked 'rest', and you'll get all instances of the searched word in a line of context. Wildcards * or ? can
The Middle Frisian corpus comprises all known 17th and 18th Century texts.
The 19th Century database includes texts by major Frisian authors.
Corpus Spoken Frisian is a sound archive consisting of 650,000 words (or 65 hours) of transcribed speech. It covers various Frisian dialects, representing speakers of various ages.
A very useful guide to creating corpora has been developed by OUCS.