In some cases I have need of a true/false or on/off selection.

Currently I am doing that through drop down options however it would be more natural in some cases to have a switch style button.

It lets the browser "click" the button without requiring initial focus first.

The following can be a workaround for the time being:

<TelerikButton OnClick="@OnSave" Primary="true">
    Save<span accesskey="S"></span>
</TelerikButton>

@code{
    async Task OnSave()
    {
        Console.WriteLine("saved");
    }
}

In some cases I have need of a button with additional options.
These options are typically put in a drop down associated to the button.

A split button makes this natural.
In this mode the user can click on the button itself or expand the dropdown and click on one of the options inside.