Here are my favourite tools (web application, commercial, and open source software) that may have affiliate links:
Atom (text editor)
Brackets (text editor)
Skitch (screen capture)
ImageOptim (image optimizer)
Zipeg (open ZIP and RAR files)
Screaming Frog SEO Spider (Mac and Windows)
f.lux – adjust the light setting of the screen (FREE)
Launchy – program launcher (Windows, FREE)
HandBrake – video converter (FREE)
Snapseed (photo editor)
Pcalc Lite (calculator)
Onto to you.
What are your favourite tools? Let me know.