Graeme Davis, who wrote a book I really like - GURPS Vikings
- posted this yesterday:
My Complete and Utter GURPS Bibliography
More stuff on their than I'd have recalled offhand, and a few I didn't notice were his (like the Knock Volley Gun in Pyramid 3/57.)
I feel an odd connection, because I was a contributing author to GURPS Low Tech, too, only in a later edition.
You can also find his extensive Warhammer, Warhammer 40K, and D&D bibliographies linked off of his site as well.