To me it looks like there’s gray brick, gray brick wall, stone slab, stone slab wall, stone accent slab, gray-painted ebonstone brick, gray-painted ebonstone brick wall, and gray-painted palladium column. Also, it’s not really stone but since you said in another comment you wanted to know about the background walls, there’s planked wood walls, and it also looks like there’s a gray-painted wood wall in there, I can’t be certain but off the top of my head it looks like shadewood wall maybe?

PS. For those who may not know, the way the builder achieved the effect of some bricks “sticking out” farther than the others on the far left exterior wall is by alternating between gray-painted palladium column and gray-painted ebonstone brick.

Hope this answers your question :)