getwebtemplates.cs

Uri uri = new Uri("https://soludigital1.sharepoint.com/sites/dev-aleksi/_api/web/getavailablewebtemplates(lcid=1033)");
HttpWebRequest request = (HttpWebRequest)HttpWebRequest.Create(uri);
request.Method = "GET";
request.Accept = "application/json;odata=verbose";
request.Headers.Add("Authorization", "Bearer " + accessToken.AccessToken);

HttpWebResponse response = (HttpWebResponse)request.GetResponse();
using (var reader = new StreamReader(response.GetResponseStream()))
{
  return reader.ReadToEnd();
}