Well I want a physical one. I have GP and there are online tuners, but I just don't force myself to use it. I feel like if I had an actual physical one to use I would.

As far as what is a good one, I don't really know. Thats kind of what Im wondering. There is the basic one like this:
www.metronomeonline.com

But that is just repeated clicks. Maybe one that allows for different beats?