SevenTV-lib implements 7TV V3 Rest API and V4 GQL API into easy to use C# library. I'll try to update this library as frequently as possible with new implementations from 7TV side.
var client = new SevenTV.SevenTVClient();
SevenTV.Types.Rest.User user = await client.rest.GetUser("01F74DWQMR0005C7FW3P0F45Y5");
Console.WriteLine(user.username);
var addResponse = await client.graphql.AddEmote("01F6WP22CR0004YCK11WAVZHEW", "01F74DWQMR0005C7FW3P0F45Y5");More on wiki
You can see examples in EmoteGuesser (pre-gql version)
SevenTV-lib is using Newtonsoft.JSON to deserialize data from 7TV API.
As SevenTV-lib is written in .NET Standard 2.1 you have to change 'Api Compatibility Level' to .NET 4.x. How to do it