Depends on the supp...
For example, Optimum Nutrition is considered the best for whey protein.
For creatine, it depends on the type. Most monohydrates are good regardless of the brand. Other types of creatine include Kre-alkalyn by EFX,
Sizeon by Gaspari,
Cellmass by BSN - All good brands for their respective creatine's. (I have used them and experienced great strength increases).
These same companies produce excellent NO products too.
Good test boosters are produced by Universal, my favourite being animal test.
So BSN, Gaspari, EFX, Optimum Nutririon and Universal are the ones i have used and have been effective.
Otherwise generic brands which produce creatine mono and things like tribulus are all pretty much the same IMO...