Specific guilds that come to mind are, for one, Tarren Mill, which is a Forsaken RP guild centered around, well, Tarren Mill. They have a Forum thread here.
The other would be the Frostwolf Legion Zetiki above is a part of. They also have a forum presence, which can be found here.
There might be a few more in the guild index mentioned, which you may find here if you didn’t already.