FreeCAD - An open-source parametric 3D modeler
Frames X - Frames X is a design system plus eBook to streamline your design workflow and help save thousands of working hours. With Frames X you will design beautiful interfaces, create great design systems, and stay up to date with the best design practices.
SketchUp - 3D for Everyone
Designment - Design On-Demand: Your UI/UX, Web & Brand Solution
Blender - Blender is the open source, cross platform suite of tools for 3D creation.
Root UI Kit - Wireframe & design starter kit ๐ ๏ธ