Commonplace books at this time seem to be an exploration of the author's thoughts and collections of what literature they appreciate, specifically political and humorous. They're kind of like diaries meant to be shared.
Search terms– su: su: "miscellany" OR "miscellanies" AND philosophy ; Hits– 2; most promising– B821 .V365 2007
Miscellanies. ... . By Dr. Swift and others. With several Additional Pieces in Verse and Prose. Commonplace books at this specific time seem to mostly be a compilation of people's own writings, arrogant visions and indices of how to live. This particular miscellany is a collection of several works compiled by and containing Jonathan Swift.