This is a minor suggestion for Leaf Piles and Dead Leaf Piles to be placeable on any material instead of just grass/dirt.
For aesthetic purposes, being able to place leaf piles only on grass is fairly useless since the most visible and common location that a builder would use them for would be in a courtyard or road bordered by trees. One of many places that leaf piles currently can't be used.

Secondary, i'd also suggesting that River Cane be placeable (which it doesn't seem to be in 1.10).