They can be cross platform, but please don’t post boring things like powertop, Firefox, or LibreOffice
I’ll go first:
LyX (sort of LaTeX WYSIWYG document editor- primarily for academic stuff)
Joplin (open source markdown/katex note application, interface is similar to Notion)
Mint’s webapp-manager utility, because I have to do alot of stuff in OneDrive for school and the two native OneDrive clients on Linux are kind of sus, and I like to open this separate (and save my password) from my normal Firefox window.
zellij: Prevents sessions from dying when my SSH connections drop-- very handy. nnn: Simple, easy to use file manager. Also good for navigation, when set up to cd on exit. nix: I can get pretty much any other package I need with this.