Supplement Safety?

My brother moved out and left behind a whole ton of supplements like creatine, BCAA, and Opti-men. Are these safe to take? I've noticed that my weight lifting hasn't been great these last few weeks and would like to continue to see improvements. I also don't want his stuff to go to waste, especially since he has a few unopened containers set to expire next year.

I'm not on any medications, so I'm not worried about drug interactions. I just don't want to start taking something that will do more harm than good.