DMT, Fentanyl, Rohypnol, hash oil, pure mdma, 100vials of pure injectable ketamine and a shitload of all the other stuff the people before me have been saying was really rare. Pure RC's are easy to come by, and I've tried many of them. Lsd is easy to get where I'm from, I can get pure ketamine any time I want in sealed vials, 2cb is not that hard to get anymore either. I've been travelling for almost a year now and you can find stuff like Rohypnol(flunitrazepam) and fentanyl, even ketamine pretty easily in pharmacies or at some chemical companies. Just make the right(wrong?) friends and you can get anything you want.
On this other forum we have a Done& to do list, there's some stuff on the done list that's hard to get almost anywhere(I haven't seen that much rohypnol floating around for example, and they are not that good by the way) and there's nothing on my To Do list that I can't get my hands on if I just ask for it.
It all depends on who you know, and travelling through countries in Asia definitely helps in finding some cheap, rare pharmaceutical drugs.
I'm not trying to impress anyone here, I've gone through a lot of trouble to get some things, but good connections should be kept, and right now I just happen to know the right people and be in the right countries to get some nice stuff. Anyone can do it. If you go to India, you can have more ketamine than you could ever possibly use for example, you just have to look in the right places is all.
It's all about location as well, in my country you just can't get any meth, and pharms like benzo's and opiates like hydro and oxy are not to be found either. But pure mdma crystals and sheets of acid(or liquid even) are not that hard to come by(don't really use either of those, don't like 'm much).
Travel and the world wide web are great sources of almost any drug you could wish for. Patience and getting in touch with the right people is key
Sorry for the long post, I'm on gabapentin with some lorazepam, which kind of makes me ramble on...