The Wizards' Guild consists of 8 unique skillsets spread over 21 orders - those of the Unseen University, their Hedge equivalents and three Illusionary Institute of Learning orders (not currently joinable) which share the same primaries as Mrs. Widgery's Lodgers.
Below is a table of each order's primaries.
- Dionysus' Handbook for Wizard Tutors - I believe this is now out of print, and even if it weren't, it's horribly outdated.
- Discworld MUD official website: the Wizards' Guild
- The Spellcheck Project
- Sekiri's Home of Wizardry (Mirror)
- Wizards & Artificers - The Love of Magical Wood
- The Wizard's Guild Wiki