* Kazam for a screen recorder (also OBS Studio, Simple Screen Recorder, and Gnome's built-in Ctrl-Alt-Shift-R) * Math Dragn (aka Symbolic Equation Manipulator) for drag & drop equation manipulation. * Notepad++ text editor (on Linux, there is also Notepadqq, available as a snap) - of course, there are *many* other text editor choices as well * WinDirStat shows you where all your drive space has gone using a graphical usage map (on Linux, there is also KDirStat & the Ubuntu Disk Usage starburst view) * VLC Media Player for playing audio & video * MuseScore for musical composition (creating sheet music) * FileZilla for FTP uploading / downloading I run Windows at work, but I looked at my list of installed applications and a whole lot are already open source: Running Kubernetes on your Raspberry Pi.A practical guide to home automation using open source tools.6 open source tools for staying organized.An introduction to programming with Bash.A guide to building a video game with Python.