Hello all, I've been working on Musical Artifacts a website for freely licensed presets and music libraries for a few months now. Now I've added support for it to act as a server for hydrogen drumkits.
You can make it work by adding https://musical-artifacts.com/hydrogen_drumkits.xml as a server in 'Import Library'. For now I've been adding free drumkits that exist around the net, but any new library registered by users with application 'hydrogen' and pointing to an h2drumkit file will show up for download inside Hydrogen.
Hope you find this useful and contribute your drums on the website!