Turning off Loop Playback

It would be great if there was a Loop Playback toggle button. More often than not, I don't want the playback to loop, as I am working on short sections of animation and I just want to flip through once as I draw. Using the timeline scrubbing is good for checking a few frames, but I also want to be able to preview the project from time to time, without looping.

Currently, I have to add duplicate frames at the beginning and end of a sequence in order to create a pause in the loop, so I can see clearly how the animation is looking - and without frame hold, this is quite inconvenient.