There was a good old RPG in the early eighties called Powers and Perils.
It was a game of tables and numbers (as was common these days) but it also contained mythological stuff from celtic, sumerian and semitic traditions. The game contained many good innovations and still feels fresh at certain points. It has indeed played a role in the forming of the world of Dominions and if you search through the game you will probably find things, beasts, spells and mythological references that you will recognize.
Avalon Hill released a world modul calle Perilious Lands. I have been toying with the idea of scanning the maps of that world. AH is a hex-company and this world is also a hex-world. I accidentally found the map two days ago scanned and ready.
http://powers.charsys.com/
http://powers.charsys.com/Images/map.jpg
The second link is the map. It's 7.6 MB. The map is made out of 23 pieces IIRC, and the seems are not entirely seemless.