What’s that one app on your phone that is utterly invaluable to you specifically. Maybe it’s got a super small use-case, but for you, and you alone it’s absolutely invaluable.
I’ll get us started…
It’s a small all that allows me to stitch photos together. I usually use it to stitch screenshots together. It’s got a nice interface and is absolutely fantastic at the one thing I need it to do.
What about you?
Syncthing. It allows you to simply sync folders between multiple Phones / PCs over the network. It works really well and kinda made cloud services obsolete for a lot of usecases.