Greater Guilds:
Masons - builders, stone
Chapmans - merchants, hawkers, traders, pedlars, sellers of anything crafted or made
Arbiters, sometimes called the 'Kibitzers' (never to their faces) or Monitors - the judges' and notaries' guild, incl. procurators/solicitors
Sacristans or 'Artisans'/'Techies'/'Tinkerers' - makers and fixers of machines (actually carriers of nanotech (augmen) that allows them to work such machines)
'Grinders' or Pedagogues - teachers, academics (incl. astrologers, philosophers and scholars), as led and organised by The Abecedary (Council of Pedagogues)
Epicureans - food, rations, etc
Atteliers or 'usurers' - moneylenders, bankers, etc
Administrators or 'Bureaucrats' - public servants, functionaries, etc.
Physicks

Minor Guilds:
Armourers - weapons and armour
Fewterers or 'Hounders', 'Conaires' or 'Keepers' - handler of hunting animals, including the Mastiffs
Remembrancers/Archivists or 'Shetari' (among themselves) - document-keepers, achivists, scribes, maintainers of the Shetar (Sacred Record)
Navigators or 'Lightermen'/'Ferrymen'- as it says on the tin (incl. gondoliers, canallers, carmen, draymen, etc)
'Leebers' or Stationers - booksellers, copyists, printers (incl. the limners who illuminate books)
Artists - incl. scriveners, painters, etc

Lesser Guilds:
'Guzzlers'  or Fuellers - sellers of fuel
Carnivaliers or 'Ragbaggers' - performers
Drovers or 'Hands' - animal handlers, farmers, etc
Cleaners or 'Rakers' - cleaners, esp. of public streets
'Hatters' or Haberdashers - tailors
'Scravers' or Prospectors/'Boothalers' - gold, archaeotech, anything of worth (also stolen goods)
'Squealers' or Heralds - promoters, gossipmongers, town-criers (incl. barkers who are flyerers and the secretive, illegal organisation known as Simurg)
Labourers or 'Tenters'
Chancers or 'Thimbleriggers' - owners of casinos, runners of games of chance and gambling, etc
Taverners - innkeepers, etc
Delvers or 'Diggers' - diggers of trenches, passages, tunnels, etc (incl. gravediggers and miners)
Founders or 'foundrymen' (incl. lampwrights and metallurgists)
Brewers - makers of booze (incl. vintners, rectifiers who purify spirits, etc)

Illegal Guilds:
Pardoners - sellers of drugs, VR games, etc
Mercenaries or 'Knifemen'
Engineers - fixers and makers of 'hard' tech (a secret faction within the Prospectors)
Barbers, AKA Fleshmongers - illegal healers, including the Frankers who perform body modifications

Unofficial Guilds, cults and sects:
Magi - The Illuminated Order of Thaumaturges
The Wheels of Purusha - a cult of Samadhists, formerly led by Markess Vyde
Mnevisians - Keepers of the Sun, temple of the artificial sun which once moved through the upper reaches of Fathomhold, now they guard the fallen satellite in Heliopolis, the Land of the Golden Fields. Led by Kemwer (the Great Black One).

http://www.svincent.com/MagicJar/Economics/MedievalOccupations.html