Been awhile since I saw a thread like this and they’re always good for at least one or two things I’ve never heard of before. Bonus points if the software is open source and cross platform. Extra bonus points if you link to where we can see it/get it.
My contribution: Destiny which is an anonymous, P2P, E2EE file sharing app - its basically a GUI for a Magic Wormhole implementation. Works on Linux (tarball or appimage), Win, Mac, Android (inc f-droid) and iOS. Only downside is it’s not been updated for 2 years.
I’m surprised how many people don’t know about a Linux utility called “fuck”. When you make a mistake on the command line and get an error, you just type “fuck” and it looks at what happened and suggests a fix. If this looks correct - and it almost always is - you just hit Enter and it types that in for you. Best thing ever!