Mideival isn't my main building style, though when I do build mideival, I use: Spruce wood planks and stairs - roofing Cobblestone, stonebrick, cracked stonebrick - foundation Raw Spruce - framing, shutters Buttons - detail Spruce and stone variant slabs - detail Though unconventional, I think the aged look of the new bone block could be used in mideival styling, if used properly and in small doses (accent block.) Oak wood plank could also work if going for a lighter look, though I think raw oak is much too dried and dull for mideival. Dark Oak is either modern, georgian, or Victorian depending on its use, so I'd stay away from it for mideival. I hope this helps! As I said, I am not a mideival builder, but I think these blocks are what the style calls for. Cheers, Buffers
Usually Gray and Brown Colors are used. Stone Bricks, Cobblestone for some Texturing, Moss and Cracked Bricks, Spruce wood and Dark Oak Wood (with fences and the appropriate block variants with those). Mostly Brown and Gray colors.