Kactus2 is a graphical EDA tool based on the IP-XACT standard.
PC based Oscilloscope and Spectrum analyzer using sound card
IEC 104 RTU Server Client Simulator Source Code Library Win Linux
Real Time Electronic Circuit Simulator.
AVR simulator IDE
Optimer: a SPICE base electrical/ electronic circuit optimization tool
RxCalc is a calculator for the analysis of multi-stage receiver.
SPICE netlist visualizer
Electronic design and programming tools suite like Eagle, MpLab
KiCad Symbol Generator (Schematic Lib)