I've used phentermine, but it really wasn't worth it. It suppressed my appetite for a few days, but then I started getting side effects (shaking, heart palpatations) and I built up a tolerance after only about 10 days of use even though I did a 4-5 days on 2-3 days off thing to prevent that
Most appetite suppressants are CNS stimulants. PPA and ephedrine both were stimulants and pretty good appetite suppressants. If you really don't want a stimulant, you could try amino acids. L-Tyrosine and L-Phenylalanine are both supposed to help suppress your appetite because they both act as precursors to your brain chemicals (dopamine, norepinephrine) and adrenaline. I personally like L-tyrosine better. Tyrosine also combines with iodine to make thyroxine, so it could help your metabolism. Start by taking 500mg in the morning on an empty stomach and see if it helps. L-Glutamine also helps with sugar cravings.