I would like to know how to summon an invisible crafting table. I'm trying to make it so that when you hold sugar, an invisible crafting table will spawn around your head. I've already got it so that a crafting table spawns around your head when you hold the sugar. Is there any way to make the crafting table invisible without using or interfering with resource packs?
Without modding the client/server no it's not. I wonder what you mean by around your head, as I didn't play for a long time. But the textures a block uses are defined by the BlockID and additional Meta-data (E.g wood:oak, where wood is the BlockID and oak is additional metadata). And the BlockID also defines the behaviour. (E.g what happens if you right click it).
By modding you can create an own invisible block (there is a block called barrier which you can extend), then defining the behaviour of that block. It is sufficient if that mod is server-side, as the GUI which is opened is invoked by the network protocol.