Blender Market offers a variety of affordable textures, add-ons, and tools for Blender users. GitHub repository "Awesome ...
BlenderKit now hosts over 1,000 free 3D sculpting brushes, integrated directly in Blender and licensed for commercial use.
LotPixel Hub beta offers over 1,300 free scan-based PBR textures for Blender users, with future support for major DCC tools.