Useful tools

ILSpy - dissasmble .NET assemblies (think Refactor, but open source)
ConfuseEx - open source .NET obfuscator
Dotnet IL Editor
SOAPUI
Fidder - acts as a system wide proxy
Squid - proxy server
WinDirStat - disk usage viewer
SlickRun - a tool for quickly starting programs
ZoomIt - useful for presentations and screen sharing
Inkscape - SVG editor
Charles Debugging Proxy
GIMP - Good free image program
Handbrake - Video transcoding (for ripping DVDs)
DVD Decrypter - for ripping DVDs
OBS Studio - Open Source streaming and broadcasting
User Agent Switcher (for Firefox)

PDF Architect used to be good, now they've ruined it. An acceptable alternative is PDF Split and Merge.

https://etcher.io burn sd cards

EaseUS partition master - the free version allows you to manage HDDs up to 8TB.