The hydrus network client is a desktop application written for Anonymous and other internet enthusiasts with large media collections. It organises your files into an internal database and browses them with tags instead of folders, a little like a booru on your desktop. Tags and files can be anonymously shared through custom servers that any user may run. Everything is free, nothing phones home, and the source code is included with the release. It is developed mostly for Windows, but builds for Linux and macOS are available (perhaps with some limitations, depending on your situation).
The software is constantly being improved. I try to put out a new release every Wednesday by 8pm Eastern.
Currently importable filetypes are:
On the Windows and Linux builds, an MPV window is embedded to play video and audio smoothly. For files like pdf, which cannot currently be viewed in the client, it is easy to launch any file with your OS's default program.
The client can download files and parse tags from a number of websites, including by default:
And can be extended to download from more locations using easily shareable user-made downloaders. It can also be set to 'subscribe' to any gallery search, repeating it every few days to keep up with new results.
The program's emphasis is on your freedom. There is no DRM, no spying, no censorship. The program never phones home.
If you would like to try it, I strongly recommend you check out the help and getting started guide. A copy is included with the release as well.