For the Hydra Products that I've been able to work on/contribute ideas to covers for, I like to play on nostalgia, but not strictly nostalgia for rpg books of the past. Weird Adventures was meant to evoke the original AD&D Player's Handbook, sure, but also the covers of pulp magazines.
In working with Jason Sholtis on ideas for a cover to Odious Uplands, I did a rush promotional cover without a lot of thought. It was fine, but neither of us were think of it as a potential final cover. In brainstorming later, I suggest we try a cover evoking the WPA Federal Art Project National Park posters made from 1935-1943:
In the meantime, though, David Johnson had done a great job of coloring the Fossil Forest image. That seemed like the cover version to use, so I made this mock-up riffing off a Fodor's Travel Guide design:
I don't know what the final cover will be, but it's an enjoyable process working with talented artists and trying out new designs.
49 minutes ago