Found 13 Slate CC0 textures in library

Dark Olive Slate
Grey Roof Tiles 02
Nero Slate Marble
Red Slate Roof Tiles 01
Roof Slates 02
Roof Slates 03
Roofing Tiles 001
Roofing Tiles 002
Roofing Tiles 003
Roofing Tiles 004
Roofing Tiles 005
Slab Tiles
Stone Pathway