Just a list of tools that I use from time to time :)

7-Zip 

Notepad++

Visual Studio Code : Free. Open source. Runs everywhere

Cmder : Portable console emulator for Windows

Rapid Environment Editor : Windows environment variables management

SoapUI : SOAP & ReST API Development and Testing environment

Postman : ReST API Development environment

WinMerge : Open Source differencing and merging tool for Windows.

mRemoteNG : is a fork of mRemote: an open source, tabbed, multi-protocol, remote connections manager.

Microsoft Remote Desktop Connection Manager 2.7

ILSpy : the open-source .NET assembly browser and decompiler.

TortoiseGit

TortoiseSVN

PuTTY

WinSCP 

Bitvise SSH Server ( windows )

Bitvise SSH Client: Free SSH file transfer, terminal and tunneling

SSH.NET is a Secure Shell (SSH) library for .NET, optimized for parallelism.

Source Code Monitor 

Visual Studio Code Metrics Powertool for Visual Studio 2013


HxD - Freeware Hex Editor and Disk Editor

Frhed ( Free hex editor )

Microsoft Message Analyzer

Audacity
fre:ac free audio converter and CD ripper

NirSoft Freeware Utilities for Windows

Sandboxie - now Open Source :)


Process Explorer [ To check which process holds the file and unlock it ]
IOBit Unlocker