This hand painted UE4 material is seamless and entirely created with blender and Unreal Engine 4.
To make it seamless I used the array modifier. Most textures are baked (displacement, normal map, ambient occlusion), later painted on a plane in blender. For painting I used a bamboo one CTF-430 (but I don't know who gave me this...). The five different stone tiles repeat, but it shouldn't matter.
I used blender 2.78 and Unreal Engine 4.16.2.