When All with results

TaskEx.cs

public static class TaskEx
{
    public static async Task<(T1, T2)> WhenAll<T1, T2>(Task<T1> task1, Task<T2> task2)
    {
        await Task.WhenAll(task1, task2);
        return (task1.GetAwaiter().GetResult(), task2.GetAwaiter().GetResult());
    }

    public static async Task<(T1, T2, T3)> WhenAll<T1, T2, T3>(Task<T1> task1, Task<T2> task2, Task<T3> task3)
    {
        await Task.WhenAll(task1, task2, task3);
        return (task1.GetAwaiter().GetResult(), task2.GetAwaiter().GetResult(), task3.GetAwaiter().GetResult());
    }

    public static async Task<(T1, T2, T3, T4)> WhenAll<T1, T2, T3, T4>(Task<T1> task1, Task<T2> task2, Task<T3> task3, Task<T4> task4)
    {
        await Task.WhenAll(task1, task2, task3, task4);
        return (task1.GetAwaiter().GetResult(), task2.GetAwaiter().GetResult(), task3.GetAwaiter().GetResult(), task4.GetAwaiter().GetResult());
    }

    public static async Task<(T1, T2, T3, T4, T5)> WhenAll<T1, T2, T3, T4, T5>(Task<T1> task1, Task<T2> task2, Task<T3> task3, Task<T4> task4, Task<T5> task5)
    {
        await Task.WhenAll(task1, task2, task3, task4, task5);
        return (task1.GetAwaiter().GetResult(), task2.GetAwaiter().GetResult(), task3.GetAwaiter().GetResult(), task4.GetAwaiter().GetResult(), task5.GetAwaiter().GetResult());
    }

    public static async Task<(T1, T2, T3, T4, T5, T6)> WhenAll<T1, T2, T3, T4, T5, T6>(Task<T1> task1, Task<T2> task2, Task<T3> task3, Task<T4> task4, Task<T5> task5, Task<T6> task6)
    {
        await Task.WhenAll(task1, task2, task3, task4, task5, task6);
        return (task1.GetAwaiter().GetResult(), task2.GetAwaiter().GetResult(), task3.GetAwaiter().GetResult(), task4.GetAwaiter().GetResult(), task5.GetAwaiter().GetResult(), task6.GetAwaiter().GetResult());
    }

    public static async Task<(T1, T2, T3, T4, T5, T6, T7)> WhenAll<T1, T2, T3, T4, T5, T6, T7>(Task<T1> task1, Task<T2> task2, Task<T3> task3, Task<T4> task4, Task<T5> task5, Task<T6> task6, Task<T7> task7)
    {
        await Task.WhenAll(task1, task2, task3, task4, task5, task6, task7);
        return (task1.GetAwaiter().GetResult(), task2.GetAwaiter().GetResult(), task3.GetAwaiter().GetResult(), task4.GetAwaiter().GetResult(), task5.GetAwaiter().GetResult(), task6.GetAwaiter().GetResult(), task7.GetAwaiter().GetResult());
    }

    public static async Task<(T1, T2, T3, T4, T5, T6, T7, T8)> WhenAll<T1, T2, T3, T4, T5, T6, T7, T8>(Task<T1> task1, Task<T2> task2, Task<T3> task3, Task<T4> task4, Task<T5> task5, Task<T6> task6, Task<T7> task7, Task<T8> task8)
    {
        await Task.WhenAll(task1, task2, task3, task4, task5, task6, task7, task8);
        return (task1.GetAwaiter().GetResult(), task2.GetAwaiter().GetResult(), task3.GetAwaiter().GetResult(), task4.GetAwaiter().GetResult(), task5.GetAwaiter().GetResult(), task6.GetAwaiter().GetResult(), task7.GetAwaiter().GetResult(), task8.GetAwaiter().GetResult());
    }
}

public static class TaskTupleExtensions
{
    public static TaskAwaiter<(T1, T2)> GetAwaiter<T1, T2>(this (Task<T1>, Task<T2>) tasks)
        => TaskEx.WhenAll(tasks.Item1, tasks.Item2).GetAwaiter();

    public static TaskAwaiter<(T1, T2, T3)> GetAwaiter<T1, T2, T3>(this (Task<T1>, Task<T2>, Task<T3>) tasks)
        => TaskEx.WhenAll(tasks.Item1, tasks.Item2, tasks.Item3).GetAwaiter();

    public static TaskAwaiter<(T1, T2, T3, T4)> GetAwaiter<T1, T2, T3, T4>(this (Task<T1>, Task<T2>, Task<T3>, Task<T4>) tasks)
        => TaskEx.WhenAll(tasks.Item1, tasks.Item2, tasks.Item3, tasks.Item4).GetAwaiter();

    public static TaskAwaiter<(T1, T2, T3, T4, T5)> GetAwaiter<T1, T2, T3, T4, T5>(this (Task<T1>, Task<T2>, Task<T3>, Task<T4>, Task<T5>) tasks)
        => TaskEx.WhenAll(tasks.Item1, tasks.Item2, tasks.Item3, tasks.Item4, tasks.Item5).GetAwaiter();

    public static TaskAwaiter<(T1, T2, T3, T4, T5, T6)> GetAwaiter<T1, T2, T3, T4, T5, T6>(this (Task<T1>, Task<T2>, Task<T3>, Task<T4>, Task<T5>, Task<T6>) tasks)
        => TaskEx.WhenAll(tasks.Item1, tasks.Item2, tasks.Item3, tasks.Item4, tasks.Item5, tasks.Item6).GetAwaiter();

    public static TaskAwaiter<(T1, T2, T3, T4, T5, T6, T7)> GetAwaiter<T1, T2, T3, T4, T5, T6, T7>(this (Task<T1>, Task<T2>, Task<T3>, Task<T4>, Task<T5>, Task<T6>, Task<T7>) tasks)
        => TaskEx.WhenAll(tasks.Item1, tasks.Item2, tasks.Item3, tasks.Item4, tasks.Item5, tasks.Item6, tasks.Item7).GetAwaiter();

    public static TaskAwaiter<(T1, T2, T3, T4, T5, T6, T7, T8)> GetAwaiter<T1, T2, T3, T4, T5, T6, T7, T8>(this (Task<T1>, Task<T2>, Task<T3>, Task<T4>, Task<T5>, Task<T6>, Task<T7>, Task<T8>) tasks)
        => TaskEx.WhenAll(tasks.Item1, tasks.Item2, tasks.Item3, tasks.Item4, tasks.Item5, tasks.Item6, tasks.Item7, tasks.Item8).GetAwaiter();
}