All the features of Ethereal Glass but an invisible block. It can be used to keep mobs, and villagers in specific areas of a building. For example an open-air Trading Hall of in large builds like a castle you can keep your villagers in specific areas so they dont all wander into a corner somewhere.

Or add a mob blocking block that the player doesn't have to crouch for. A Barrier Block that only effects mobs and villagers.

Hey, sorry for the late reply, but being invisible kinda defeats the purpose of being glass..

However you might want to have a look at the Entity Barrier from Peculiar Pieces, it does exactly what you are asking for!