title: Is there an AddUnique method similar to Addrange() for alist in C#
body: <p>I have a list in C#:</p>
  
  <pre><code>       var list = new List&lt;Car&gt;();
         list.AddRange(GetGreenCars());
         list.AddRange(GetBigCars());
         list.AddRange(GetSmallCars());
  </code></pre>
  
  <p>the issue is that some of the same cars get returned in different functions and I don't want them  in the list more than once.  Each car has a unique Name attribute.  Is there anyway I can have something like this above but will only add items if they are unique ?</p>