There are a number of lists of the 110 livery companies of the City of London:
Livery Companies Database - with contact details and masters' biographies
LiveryCompanies.com - an alternative to the above, but with some additions (see below)
London Footprints - brief historical and architectural descriptions of each livery hall
Mottos of all the livery companies
The first named above, the official Livery Companies Database, is updated by the individual Company Clerks, and shows their masters, wardens, and contact details, and following the relaunch in October 2015, much else besides, including Google maps links to halls, pictures of the master's badge, and pdf's of masters with their photo.
The second site, created and maintained by a past master Tyler, and sponsored by The Cook & The Butler, shows broadly the same information, in a rather different format. The current edition of the Masters' Picture Book (edited by Piers Nicholson) can also be downloaded from this site (ditto for Consorts). This second site is NOT the responsibility of the Livery Committee.