using System;
using System.Linq;
using System.Text.Json;

string[] names = {"Max", "Tom", "Anna"};
var teams =
    from name1 in names
    from name2 in names
    where name1.CompareTo(name2) > 0
    select name1 + " and " + name2;
//teams is { "Max and Anna",
//           "Tom and Max",
//           "Tom and Anna" }

Console.WriteLine(JsonSerializer.Serialize(teams));