I use Multi, Fish Oil, Creatine, Vitamin D (night shift vampire crew checking in), vitamin c, and caffeine/preworkout. On or off cycle I use all that. Some of the most godly pumps I ever got were running Test Blend/EQ/Var and taking a preworkout or a cialis beforehand. But never both because you can have a dangerous drop in blood pressure if you combine cialis with nitrates.
Protein powder I don't consider a supplement. Its a food source.