Python! The simple yet powerful programming language behind everything from Dropbox to 2017's, "Doki Doki Literature Club," is also open source. With many powerful frameworks to its name and many resources for getting started, Python is an easy language to pick up, and a powerful ally.
Cross-platform, free media player supports multimedia files, DVDs, streaming, offers hardware acceleration, 4K, lossless audio, and more.
I'm not even sure this is open source, but it enables the riddance of proprietary software.
Honestly, I don't remember putting this one on this list, but it can't be that bad if it isn't a virus.
Mozilla Firefox, usually called by the latter part of its name, is a well-known web browser that is entirely free and open source.
MuseScore is an open-source application for sheet music composition. It also interacts with MIDI devices that can control its built-in instruments.
Blender is a free and open source 3D modeling and animation written in Python. It is a viable replacement to similar programs like Maya.
Inkscape is a vector graphics editor with capabilities comparable to Adobe Illustrator CC. It is free, open sourced, and crowd-sourced by its community.
Open Broadcaster Software, or OBS, is an open source, cross-platform screen recorder that allows for streaming to many sites. It replaces these services' proprietary streaming tools.
iTerm2 is a terminal emulator for macOS that allows for a great deal of customization, while also being incredibly functional. It acts as a replacement to macOS' preinstalled terminal emulator.
For users running platforms other than macOS, (or Mac users who are control freaks (that is to say, Mac users.)) Hyper fills the role of the clean-looking, powerful, and highly hackable terminal emulator. Hyper is built on another open-source framework, GitHub's Electron, and uses HTML, CSS, and JavaScript for much of its code as such. It replaces its platforms' preinstalled terminal emulators.
Despite being developed and maintained by the once notoriously proprietary software company Microsoft, Visual Studio Code is a fully functional, general purpose code editor with several professional and innovative features. Like Hyper, it is built on GitHub's Electron framework.
