An open source online viewer of KiCad schematics and boards
Open-Awesome is built by the community, for the community. Submit a project, suggest an awesome list, or help improve the catalog on GitHub.
Syntax highlighting for various PCB (Printed Circuit Board) formats.
An embedded engineering calculator toolbox for doing calculations in a breeze
Parts library with free symbols & footprints. (Compatible with Eagle, KiCad, Altium, OrCad, Allegro, etc.)
The Saturn PCB Toolkit is the best freeware resource for PCB related calculations you can find