B vitamins in general support energy levels and so on. I've seen a number of sources that suggest a B-complex vitamin may be beneficial for bipolar (and is generally helpful for anyone with low energy levels).

I'm planning to ask my pdoc about Omega-3's, folic acid (one of the B vitamins), and vitamin D when I go in next. There's not much likelihood that taking these supplements would cause problems, but since everything anywhere says "check with your doc" once you start dealing with bipolar meds, I figure it's better to be safe than sorry.