List<string> botones = new List<string>();

        botones.Add("Filipenses 4:13");
        botones.Add("Juan 3:16");
        botones.Add("2da Timoteo 3:16-17");
        botones.Add("Salmos 23:6");
        botones.Add("Salmos 91:1");
        botones.Add("Romanos 5:1");


    {

        Random r1 = new Random();
        indexBtn = r1.Next(botones.Count);
        txtBtn = botones[indexBtn];
        botones.RemoveAt(indexBtn);

        Random r2 = new Random();
        indexBtn2 = r2.Next(botones.Count);
        txtBtn2 = botones[indexBtn2];
        botones.RemoveAt(indexBtn2);

        Random r3 = new Random();
        indexBtn3 = r3.Next(botones.Count);
        txtBtn3 = botones[indexBtn3];
        botones.RemoveAt(indexBtn3);

        Random r4 = new Random();
        indexBtn4 = r4.Next(botones.Count);
        txtBtn4 = botones[indexBtn4];
        botones.RemoveAt(indexBtn4);
       botones.RemoveAt(indexBtn4);

        Random r5 = new Random();
        indexBtn5 = r5.Next(botones.Count);
        txtBtn5 = botones[indexBtn5];
        botones.RemoveAt(indexBtn5);


       Random r6 = new Random();
       indexBtn6 = r6.Next(botones.Count);
       txtBtn6 = botones[indexBtn6];
       botones.RemoveAt(indexBtn6);



        Btn.Text = txtBtn;
        Btn2.Text = txtBtn2;
        Btn3.Text = txtBtn3;
        Btn4.Text = txtBtn4;
        Btn5.Text = txtBtn5;
        Btn6.Text = txtBtn6;


    }

Random r1 = new Random();
indexBtn = r1.Next(0, botones.Count-1);