Biotest is very reputable (that's my impression anyway) for supplements geared towards weightlifters.
https://www.t-nation.com/store
They have stuff in their "Health" category with broader appeal (Superfood is pretty cool). I've been very pleased with what I've used from them.
A friend of mine told me she got very good results from Vitamin World melatonin, and little or no effect from Natrol melatonin, and that reminded me of recent news that many herbal supplements don't have any herbal content.
Does anyone have information, whether based in personal experience or from studies, about which brands are more reliable about their contents?