TurboSquid - TurboSquid offers 3D models for professionals.
Elements for Sketch - High-quality UI Kits in Sketch, for free
STLFinder - The 3d models search engine.
Tailwind CSS - A utility-first CSS framework for rapidly building custom user interfaces.
3DOcean - 3D Models & Accessories From $1 for 3D Models, Textures, Materials & Shaders, 2D Concepts...
DynaMaker - Cloud service for Visual Product Configuration with parametric geometry and CAD / BIM