Most things that stimulate brain is "nootropic".
So, caffeine, reading, learning, stimulating senses, training memory... and so on.
Reddit has nootropics channel which is good for news in this area of science.
https://www.reddit.com/r/Nootropics/
As for miracle drugs (like in Limitless movie & serrie) I have not come across anything that improves cognition significantly in short time yet.