There's a file-sharing app using I2P that's been revived. It's currently not under active development, but it is fully functional as-is.
As always, be careful with unknown programs. I take no responsibility for anything related to the program.
The file can be downloaded from within I2P, or here: https://ufile.io/y1uecxev
If you want to know more about I2P technology and anonymous overlay networks, go to https://geti2p.net/en/