CircuitMaker

CircuitMaker is the best free PCB design software by Altium for Open Source Hardware Designers, Hackers, Makers, Students and Hobbyists. From the about page of the website:

FREE TO USE, AND POWERFUL CircuitMaker is the best free-to-use schematic and PCB design tool for the Open Source Hardware community. We think that just because you’re willing to share your work and passion for electronics, doesn’t mean you should have to use second-rate design tools. We think, that if you’re giving back to the community, you deserve something that will help, not hinder. But CircuitMaker is more than just a free schematic and PCB design tool - it’s a vibrant community of open source designers, makers, hobbyists, students and professionals working together to make exciting new products every day.

CIRCUITMAKER IS BUILT BY ALTIUM CircuitMaker is built by Altium, so you can have complete confidence in the technology that drives most of the world’s PCB design activity. We wanted you to have access to technology without restraining your creativity or ability to collaborate. That’s why we’ve included powerful routing, hierarchical schematic entry, autorouting, and Native 3D™ technology. It’s also why we built the CircuitMaker community workspace with team project management and collaboration features in mind.

YOU WILL FIND A FAMILY OF ELECTRONICS ENTHUSIASTS At CircuitMaker, you will find a family of electronics enthusiasts willing to share and contribute and support each other, from encouraging comments to full on teamwork, and crowd-sourced libraries, and everything inbetween. We’ve partnered with key content providers so you can find tested reference designs and fork them into your own adaptations. Then when you’re ready to go to production, you can generate a project release, and optionally send the job to one of several high-quality one-click manufacturing partners.