I haven't read through the entire thread, but if we're counting phenibut as a nootropic, I've had a really interesting experience combining it with around 13-15mg 4-AcO-DMT (intranasally). The visuals were reduced, but the ego-death was greatly increased. It wasn't full ego-death, like when you forget who you are or even that you're a human, but enough that I wouldn't trip socially. It was an intense trip and probably the most spiritual one I've ever had, I "saw" the afterlife and stuff like that. I was on about 2 grams of phenibut. I would absolutely do this combo again if I felt like experiencing something that profound again, but I wouldn't do it frequently or with pure recreation in mind. Normally, the same dose of 4-AcO-DMT would be an introspective but easily manageable dose that I can (although still don't prefer to) do socially, and very visual+colorful. I agree with Xorkoth that phenibut added a slightly manic but euphoric edge. Crazy good afterglow too, lasted for two or three days.