fantasy
>the deep dark underdoom of dungeons (many sub-types)
>the rising and falling sky high islands that never seem to end
>a world of many diverse biomes
yeah you can pretty much come up with anything
my examples may be only fantasy
but scenarios usually work better if youre planning on including "group playing"
coop players up in a high pressure, tense action, no mistake submarine sinking to the bottom of the ocean, and theres sure to be thrill made!