KiCad: A cross-platform, Open Source suite for electronics design automation that effectively manages schematic capture and PCB (printed circuit board) layout. MajorGeeks also has the portable version.
KiCad Portable is a robust, cross-platform Open Source suite designed for electronics design automation. It effectively handles both schematic capture and printed circuit board (PCB) layout, catering to a variety of design requirements. It supports multiple output formats, including Gerber files, making it a versatile choice for designers. Installer, Linux, and Mac versions are also available.
SketchUp is an easy-to-use web-based program that will help you learn to create 3D models of houses, sheds, decks, home additions, woodworking projects even spaceships.
Tinkercad is a free, easy-to-use app for 3D design, electronics, and coding. It's used by teachers, kids, hobbyists, and designers to design and make anything.
TopSpice is an integrated electronic circuit design system with multiple capabilities, including schematic capture front-end, mixed mode simulator, graphical representation, and library of over 35,000 device models.