LTspice - LTspice® is a high performance SPICE simulation software, schematic capture and waveform viewer with enhancements and models for easing the simulation of analog circuits.

Calculatoredge - calculators, engineering, mechanical, electrical, electronics, design, construction, manufacturing, consultant, layout, software, chemical, plastic, polymers

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.

FreeFlight Pro - FreeFlight Pro is an entertainment app that comes up with features to help users in piloting their drones right through their mobile phones and other smart devices.

KiCad - A Cross Platform and Open Source Electronics Design Automation Suite

Electronics Assistant - Electronics Assistant is a Windows program that performs electronics-related calculations.