Another great resource I use in my Primeval Thule campaigns is the World of Xoth stuff by Morten Braten. It's all written for Pathfinder so it's pretty easy to convert. The website has a couple of freebies but the main PDFs are really reasonably priced.
http://xoth.net/publishing/
When I was looking for Thule suitable third party resources I looked hard at using The Spider God's Bride adventures, but ultimately rejected the idea. Reasons:
1. They are very much written with a 'Conan in Zamora/Shem/Zamboula' type feel, which is surprisingly distant from Thule's tone. They're very Orientalist, versus Thule's more of a Lost World feel.
2. They are mostly set in deserts and dry plains, non-Thulean terrain.
3. They are rather over-written (rather like Paizo stuff) in the interest of creating a baroque mood, and I was finding them hard to decipher given they would need extensive conversion for play.
Not a bad product if you are running a specifically Conan game set in his typical adventuring locales, but for me they didn't work. Instead further digging brought up The Midlands book I mentioned, which also has tons of swords & sorcery themed adventures, but the writing is much less baroque and use at table seems far easier.