As you can tell by my screen name, I've been an oneironaut for as long as I can remember. I've been writing down my dreams since I was about 13, and I'm in my 50's now. Luckily I've always had very vivid, memorable and often lucid dreams, because the supplements don't do much for me.
Calea Zacatachichi - I had one crazy dream the very first night about an animated purple cow, but I tried it for another month and nothing memorable happened.
5-HTP - Gave me horrible nausea upon waking up. I tried it twice and just couldn't tolerate it.
L-Tryptophan - My stomach tolerates this fine, but no interesting dreams to speak of.
Melatonin - Actually keeps me awake and gives me anxiety.
Huperzine-A, Alpha-GPC, Choline, etc. - Expensive and didn't do anything.
Bacopa Monnieri - Same as above. (NOTE: Do *not* snort it. I tried it once as an experiment, and it literally felt as though I stuck a long dagger up my nose and out the back of my head! This is coming from someone who has insufflated some pretty strange things over the years as well.)
Valerian Root - Helps relax me a bit but no exceptional dreams.
L-Theanine - Same as above.
Kratom - Keeps me relaxed but awake, even the mellow strains like Red Vein Bali.
Kava Root - Unbearable nausea.
Alcohol and Weed - Kills my REM sleep altogether.
There are only two substances that ever gave me really epic dreams:
1) The antidepressant Remeron (Mirtazapine) when I first went on it, but that effect disappeared quickly.
2) Nicotine Patches, but they make it hard to fall asleep from the stimulation.
Furthermore, I don't recommend using strong chemicals just for dreaming purposes.
Oh yeah, and withdrawal dreams (opioids, benzos, alcohol) are insane when I can finally sleep. But again, it's not worth getting addicted to a life-ruining drug just for a couple of cool dreams.
Sweet Dreams!!!
Dreamflyer