Programming
Embarcadero Dev-C++ is a new and improved fork (sponsored by Embarcadero) of Bloodshed Dev-C++ and Orwell Dev-C++. It is a full-featured Integrated Development Environment (IDE) and code editor for the C/C++ programming language. It is useful to have in a malware analysis VM to quickly prototype C programs using the Windows API, writing loaders, patchers, etc.
The flat assembler (fasm) can be very useful while reversing stuff. For example, you may want to create an executable from a binary payload (some people would call it a "shellcode to executable conversion") this way:
Also, there are many interesting source code examples in the %AppFolder%\fasm\examples directory.
Portable Python 3 interpreter, command prompt, GUI and famous tools all together. It is used in retoolkit mainly to execute the Python-based tools shipped with it, but you can also use it for doing whatever you want with Python. 🐍