In my recent adventures, I recall two clear influences.
Another involved a room with false-floor tiles with runes on them, where certain tiles are safe to step on and others lead to a nasty fall. This was inspired by Indiana Jones and the Last Crusade.
Inspiration for the current campaign I am working on is Janny Wurts' Wars of Light and Shadow series.
Several other things that folks have mentioned have played in a part for inspiration in the past as well and are all good suggestions. Some new ones too that I will definitely have to check out. Anything by Carol Berg I think is good fodder as well.
scooby do. .

(Dungeons & Dragons)
Rulebook featuring "high magic" options, including a host of new spells.