This will probably get closed as it doesn't fit the "harm reduction" angle we operate under here at blue light but I'll try to help...
You can check out the "List of designer drugs" page on Wikipedia. It has a pretty extensive list but I'm sure there are a ton not on there. Beyond that I don't know where else would be best to look... search around the internet a bit perhaps?
A list of research chemicals that were either once available or currently available would be constantly growing in size and a list of all the possible research chemicals that could be made would be HUGE and constantly expanding as well.