Here's a PDF of some D&D dungeon tiles, as well as your normal 'dungeon décor' of statues, ruined pillars, pools, fountains, magic circles, ect - it also includes a small tavern and a building full of book cases which could be used as a wizard's study or library type building
Just realised how flexible these are. This surprises me a little because I always feel that the pressure is on to make square tiles only because that's what most of the competitive products are atm - and the fact that large square tiles don't slide around as much. These are much more like the old Dungeon Floor Plans of yore. Hmm. Interesting.