KiCad - A Cross Platform and Open Source Electronics Design Automation Suite
GoodBarber - GoodBarber is a mobile app creation platform.
Proteus PCB design - Proteus PCB design combines the schematic capture and ARES PCB layout programs to provide a...
Siberian CMS - Siberian is an Open-Source and Free App Maker. Unlimited Push Notifications. Unlimited features. Fully Customizable. Download it and build your own app now!
QUCS - Qucs, briefly for Quite Universal Circuit Simulator, is an integrated circuit simulator which means you are able to setup a circuit with a graphical user interface (GUI) and simulate the large-signal, small-signal and noise behaviour of the circuit.
Dropsource - Mobile development platform for building native iOS & Android apps