There isn't really such a thing as a "warm up exercise". Exercise is exercise. Some is higher intensity than others. Some low, and some high, intensity exercises are typically done before a 'work' part of a workout, but they're not by definition "warm up exercise" and can be incorporated into any workout as challenging components themselves.
What is it you do for the work part? Are we talking about warm up for ST, walking, swimming, dance class, or what?