Got a purpose in mind for this guild? Are we talking about bounty hunting, a holy order, or something completely different? It would help a little bit to know more about their purpose, since a name should help reflect the attitude and theme of a guild. Helps tie in people's attention.

That said, I'm going to throw in a few.

Order of the First Dawn
Order of Dragons
The Guilded Compass

And the ever popular secret/thieves guild...The Hushed.