Arguably, the cover of GURPS Basic Set, Third Edition Revised, published by Steve Jackson Games in the 1990s, is plain and undramatic, without a strong central element upon which for the eye to focus and then travel around the scene. (For an example of that, check out the cover of Mutants & Masterminds, Second Edition.)
I first ran into this piece of work during one of my many near-hits with roleplaying. Someone on a Doctor Who mailing list — probably the now-gone House on Allen Road, maybe Jade_Pagoda — posted a link to the basement of Steve Jackson Games’ Warehouse 23, where one can roam around, opening crates in the archetypal repository of the bizarre and impossible. Eventually, I went from the warehouse to the company’s GURPS pages. The concept of modular design, where you buy books with the rule and setting elements you need to facilitate a particular concept, really appealed to me, to the point I spent a lot of time mulling over which books I would like, even though at the time I had no way to utilize roleplaying game books or even a strong conception of what roleplaying entailed.
The things I like about this cover, enough that I remembered the image from that fleeting contact years later when I really got into RPGs in mid-2002, are the combination of diverse elements, the questions they ask and overall austerity of the design.
There’s a castle, what look like mysterious ruins in the foreground, a rider on the horizon and jets taking off, all while a neighboring moon or planet hangs large in the sky. That covers a wide swathe of genres in a way that, for me, provokes questions: why is the rider going to the castle? Are the jets attacking or on patrol? Is there supposed to be a galaxy naked to the visible eye, or is that what provoked the rider and the pilots to action?
Plus, it’s a nice landscape. I wouldn’t mind a print of that to hang somewhere.