Add multiple instances of a property to a list
You can shorten the first part to 3x this:

var teamAverage1 = Players
    .Where(p =&gt; p.teamId == id &amp;&amp; p.a == 'x')
    .Select(x =&gt; x.Average1)
    .ToList();


I don't like the p.a properties. They look like a bad design. But it's hard to say more from the snippet you've showed.