I've never tried Amphetamine but I use Modafinil, Armodafinil and Phenylpiracetam pretty regularly. They're all excellent performance enhancers IMO, and they don't feel too bad for you either. I don't think that combining them is particularly smart though, or even really necessary. A far better option is to cycle them to keep tolerance in check.
In my opinion and experience Phenylpiracetam is a little less punishing on the body because it has a shorter duration and doesn't dehydrate you (as far as I know) whereas ~afinils last a long time and do seem to have a dehydrating effect.
Additionally even though the incidence of cardiac side effects is very low, I believe that they have been documented in ~afinils, and although I consider myself to be in pretty good health and try to keep my usage in check, I have occasionally experienced "twinges", for lack of a better word, I don't know if this is really indicative of any unwanted cardiac goings on but it's enough to make me more wary of using ~afinils as performance enhancers too often.
But yes, of course they are all well known substances now, Meldonium included, and will definitely be tested for if that is a concern (although I don't see that the OP necessarily implied that it was relevant, for professional athletes obviously it would be).