Rare pharmaceuticals
On the topic of rare pharmaceutical drugs, I don't think anyones mentioned what is one of my favourie stimulants; fencamfamine.
It used to be marketed in a combination of vitamins as Reactivan; if you ever come across any, jump on any chance to acquire any. A dose of 10-20mg is about on a par with 5mg of dexedrine, but there are next to no physical side effects, like racing heart, intestinal churning and no lack of appetite. In fact, about the only noticable physical side effect is a dry mouth, but that requires in excess of 50mg to become noticable. Psychological side effects can't be avoided (the paranoia/insomnia etc), but are much less distressing, due to the lack of physical symptoms to back them up.
All in all, it's so smooth on the body that if I could still get it, I'd not want to touch amphetamine again (but I fear those days are long gone)