I dislike the term nootropics because is actually has a tight definition that most things don't fall under. "Cognitive enhancers" or smart drugs is a much better term although it's vague.
Really depends on what you're looking for, but I can give a list of some of the most powerful and effective cognitive enhancers, trying to put them in order from strongest to weakest though that's really hard to say.
- Alpha GPC / CDP Choline
Many supplements also can have strong cognitive effects such as creatine, phosphatidylserine, fish oil, uridine, l-phenylalanine / l-tyrosine...
There's also longevity/neuroprotective supplements, ie resveratrol, NMN, metformin , selegiline...
Then there's well known ones, such as caffeine, kratom and nicotine. Nicotine in particular is actually one of the most powerful cognitive enhancers ever. Not even going to mention stimulants like adderall etc, they're so far from being a nootropic it's not even worth mentioning them all.
Lastly, I've never been on psych meds so I cannot answer your 2nd question, but it would depend on what you're trying to get off. There are some possible solutions, including naltrexone, and possibly memantine. There are also things you can use to "wean off" benzos such as Phenibut, or weaning off opiates with certain Kratom strains.