Better Slabs is a mod that intends to improve the functionality of slabs by adding vertical variants to all slabs, modded or vanilla. Unlike other vertical slab mods, Better Slabs automatically makes vertical slabs by generating resources at runtime. This eliminates the need for a separate vertical slab item, or the need to manually add support for other mods. So what are you waiting for? Give it a download and try it out!
NOTE: this is a fabric mod and I have no intention of releasing a forge version.