SW

You can find here links to good applications for engineering work. Most of them are free and on-line.

Common using Apps

Draw.io - a perfect on-line drawing application
Design Spark - this is a SW package including mechanical SW, electrical SW, PCB SW, safety SW and DS toolbox
FreeCad - a parametric 3D modeler made primarily to design real-life objects of any size
DraftSight - a powerful 2D drawing application
3DReshaper - a complete toolbox for 3D modeling
WolframAlpha - a very complex computing tool using breakthrough algorithms, knowledgebase and AI
Falstad - a lot of different hobby applets (oscillations, signal processing, etc.) with a little bit poor appearens

Multisim - a very known tool for both circuit design and simulation from National Instruments (formerly Electronics Workbench)
123D Circuits.io - a very proffesional tool based on the former Eagle application. It is now an AutoDesk property.
PartSim- a very good circuit simulation
CircuitLab - circuit simulation and schematics
EveryCircuit - very nice animated simulations
iCircuit - another mobile app that will appeal to students, hobbyists and engineers
Quite - a circuit simulator with graphical user interface
TINA - a powerful yet affordable circuit simulator and PCB design software package
DC/AC Virtual Lab - a circuit simulator with real life experience