Misq is an official .NET Misskey library.
available on nuget
// Create your app instance
var app = new Misq.App("https://misskey.xyz", "your app's secret key here");
// Authorize user
var user = await app.Authorize();
// Let's post a message to Misskey
user.Request("notes/create", new Dictionary<string, object> {
{ "text", "yee haw!" }
});