Pick Three Random Objects From Array (No repeat)

So I’m trying to make a level up system where when the player character levels up, he can choose to pick a power up from three random power ups, I made an int array that stores every power up and their respective levels, as you can upgrade a power up that you already picked before. But I’m not sure how to pick three numbers from this array without repeating, Googling also didn’t help :\

This works fine for me

    List<int> numbers = new List<int>()
    {
        1, 2, 3, 4, 5, 6
    };

    int number1 = numbers[Random.Range(0, numbers.Count - 1)];
    numbers.Remove(number1);

    int number2 = numbers[Random.Range(0, numbers.Count - 1)];
    numbers.Remove(number2);

    int number3 = numbers[Random.Range(0, numbers.Count - 1)];
    numbers.Remove(number3);