Vertical slabs is a simple, vanilla-like mod that adds vertical slabs to Minecraft.
* image taken with v1.9 of the mod
as of v1.10
As of v2.5
Showcase of what can be built in Enchanted Vertical Slabs 1.8 and above
as of v1.9.3
Slabs appear with other blocks of the same material in the creative inventory as of v1.7