7-Zip

18.05

Free

Main tool for compressed archives, in either 7z or zip format. Also works with tar and tgz.

cloc

1.8

GPL 2

Tool to count lines of code, supporting many different languages, with very good configuration and exception handling.

Doxygen

Framework to generate documentation from annotated source files. Originally written for C++, but can be used for other source files as well. Generates large documents (if required), with complete API references, even including UML diagrams.

Pandoc

Swiss Army Knife for document conversions. Can virtually convert any document (source) into any other document (source).

WinsCP

Free application to handle remote copy and FTP. Windows only.