Cobblestone texture packs
Turn a pack on and every cobblestone block in your world takes its new look, wherever you have already placed one. Stairs, slabs and walls made of the same material usually change with it, because they share the texture. Nothing about the block itself changes.
How it works
Download the pack, open the .mcpack with Minecraft, then turn it on under Resource Packs in your world or under Global Resources in Settings. Step-by-step for your device.