Ok I have been thinking about this and I thought of some new attributes and layers. I will list them below.
Slippery (if your character steps on one of these then they keep sliding along all other slippery tiles in the same direction until you hit something not slippery.This would be good for ice.)
Flash(Unlikely) This would allow you to watch movies in game and play miniature games.Can use it for a movie theatre or arcade.
Unnamed Ok i dont know what this one would be called, but it would be good if all the tiles on this layer would dissapear if a character walked under it. Like fringe, but the tiles dissapear. This would be good for tall buildings that have paths or smaller buildings behind it.
I might think of more. Tell me what you think and give me more ideas.