Finders' Guild of Sigil
From Ardrana
The Finders' Guild is a loosely associated group of individuals who make their home in Sigil. They claim to be able to find anyone or anything -- for a fee, of course. There is not, at present, a formal location to seek out these individuals, however, one can obtain a list of "specialists" thru inquiring at Sigil's Red Dragon Inn -- for a fee, of course.
The current guildmaster is Linthius Fanek.