The Soft Blocks mod allows you to control which blocks don't have fall damage.
The Blocks which should not have fall damage are selected by a configfile.
Just type in the name of the block that should not have fall damage. 

This supports mods and also none full cubes like lilypads or half slabs.
Metadata or BlockStates are not detectable since thats not really needed.
This also effects only players

Thanks to Princess who made the logo