I remixed the OpenForge Ruined Floor Tile to have a connection set on the bottom that will allow them to lock together using the tiny connector that is included in the file.
I like the idea and depending on the other tiles I use, I may add the connector to other tiles as well. I like the idea of having them lock, rather then loose fit.
(Not completely knowing the history of OpenForge or Dwarven Forge I modified the height on the tile, it may be a bit short for true compatibility)
Updated I added a Openforge standard version that is the same height as the other tiles. This should make them mixable with any of the other sets.