Kodi Add-ons

OpenStreetMap
A script that allows you to access OpenStreetMap from within Kodi.
OpenVPN
A script that allows you to control OpenVPN from within Kodi.
Similar Tracks
A script that uses the currently playing track to generate a playlist of similar tracks in your Kodi music library. Uses the Last.fm API.
TuneIn Radio
A plugin that allows you to access thousands of radio stations at TuneIn from within Kodi. Uses the TuneIn API.

Development Resources

Kodi Python Modules
List of modules that can be used when developing addons for Kodi Helix.
JSON-RPC API v6
JSON schema documentation for Kodi Helix.
Kodi Forum
Kodi community forum. Useful for add-on development questions.
Last.fm API
Last.fm API documentation.
OpenVPN manpage
Manual page for OpenVPN, contains summary of some of the features of OpenVPN.