I have in my time collected dictionaries, though often it was for utilitarian purposes, so photocopies rather than books.
The one I think of with the most affection is John Sampson (linguist): The dialect of the Gypsies of Wales. It’s uncompromisingly scholarly, from a time when the Roma were considered beneath the notice of decent society. And Sampson himself was a pretty amazing character.
Is it just me, Kelley Spartiatis, or is everyone from Liverpool amazing? 🙂