Data Dragon is the official Riot Games API for accessing League of Legends champion and item information. It’s a bunch of static assets (JSON data + images) vended via Riot’s CDN and updated whenever a new game patch is released.
When I built League Handbook several years ago, I couldn’t find any good .NET client libraries for Data Dragon, so I ended up writing my own. While the source code for League Handbook (including the client library) has always been available on GitHub, I wanted to make it simpler for other developers to consume the library, so I went ahead and published it as a NuGet package today. Check it out if you’re looking for an easy way to pull champion/item information into your .NET project (and feel free to share your project in the comments below).