Quickly make copy-pasteable commands to get all sorts of things done: all these apps are available for Linux, Raspberry PI, Windows, macOS, and Android, either pre-installed or as downloads
The stream editor is a highly-configurable text processor, and comes pre-installed on Linux, Raspberry PI, and macOS
An extremely-configurable audio/video processor, which supports all commonly-used AV formats, despite what its name suggests
A handly audio/video file downloader: despite its name suggesting it's only for YouTube, it supports all the big AV sites from around the world