The items below are things I’ve created for use in my dungeons, mainly in Gametable although these would work just fine in OpenRPG as well. They’re formatted for a scale of 64 by 64 pixel squares representing five feet in the game world. Note that the long, skinny objects, such as a stairway that’s two squares wide but four squares long, is made up of an image file that’s four squares by four squares with the stairway off to one side and the rest of the image being transparent (for easier placement within Gametable).
All images are intended to be more or less overhead views of the objects in question (sometimes with a bit of an angle on them so that you can see what they are). Some are complete homebrews by me (you can tell by the crappy art quality) while others are cribbed from images I found online. As always, if any of the images belong to you and you wish me to take them down, just let me know.