Check out Carved Stair 02 Black Low-poly 3D model on CGTrader for $15. High-quality mesh by shabnam3dart: 347400 polys, 373587 vertices.
MAX (Autodesk 3ds Max, filesize: 33.6 MB), OBJ (OBJ, filesize: 32.4 MB), FBX (Autodesk FBX, filesize: 15.8 MB), STL (Stereolithography, filesize: 46.9 MB)