Pretty self-explanatory mod, it add vertical slabs for all vanilla slabs as well as crafting recipes and stonecutter recipes.
All vanilla slabs have alternative vertical formats that can be placed on either end of a block. These allow you to basically create half block walls of sorts. You can craft these via three of block in a vertical pattern in a crafting table or by putting a block in a stone cutter.
I'll update the mod with more slabs, when minecraft adds new slabs to the game.
Edit: Added 1.15.2 version.