This mod adds all the stairs you could want by including various stone types that have typically been omitted in standard Minecraft. So all the standard stone blocks like Diorite, Andesite, Granite, Obsidian, and many others can be made into stairs.
As well as End Stone, Prismarine, Concrete and even Wood!
In addition to stairs you can also craft all sorts of slabs and walls. These can be made from cobblestone blocks, bricks, and polished blocks as well.
Various stone types will now break into Cobblestone versions that can then be turned into their stone versions and polished and then chiseled versions.
And moss can be crafted into all the new stone bricks! That includes all blocks, slabs, walls, and stairs.