What things should NOT be on a VTT map?

[Redrobes]

Coffee stains.

heh nice...

Tis a can o worms that question to which many megs of web serving harddrives have been consumed.

My opinion... anything that you either want to change during play or really would not want on it when you come back to it a long time later. I am not as anal about it as some tho where anything more ephemeral than the bedrock should be omitted

Grids are a bit special as its not part of the map but more a construct of the mapping process. A grid is alright sometimes but the VTT app can do more if it owns the grid so that kinda depends on the app. Same goes for trees. I have no problem with my own trees but as a single flat bitmap you can't magically go under any umbrella shaped objects.