One stimulant not mentioned is adrafinil, the prodrug of modafinil, whichever one you can get your hands on. I find adrafinil doesn't give me the crazy heart rate increase that adderall does, and so it's a lot easier to take preworkout. I remember the first time I used adrafinil I got some heart rate increase but after that it never did it again.
It also doesn't give you the catabolism that amphetamines do, or at least it doesn't seem to hurt my strength in the gym while the few times I tried adderall preworkout I definitely felt some lost strength. I read a while ago that amphetamines are catabolic to muscle, but have never been able to find a source (ie, scientific paper) on it.
I also like piracetam and aniracetam. I usually only use aniracetam with adrafinil though because it can make you a bit lethargic. Sometimes I feel like the calmness I get from aniracetam is good though because I can get real focused for heavy olympic lifts like power clean, clean & press and snatch. Piracetam is great mixed with caffeine, especially with good music on your headphones. I find piracetam really makes me get into the music while I workout. I pretty much suck at working out without my mp3 player lol.
I get a lot of supplements from biotest. They have a number of great products to use preworkout. Their energy drink spike shooter is great, but it has yohimbine in it so if you are not used to them they will send your heart into overdrive at first. I have a huge tolerance to them now after drinking them for a number of years so it's nothing for me. Also their power drive is excellent. It is another light stimulant, and can get your heart going from the tyrosine especially if you're not used to it, but once you use it a few times you will understand. The DMAE in it also works great as your choline precursor to mix with any of the racetams.