Almighty Wikipedia: nootropics are "drugs, supplements, nutraceuticals, and functional foods that improve one or more aspects of mental function, such as working memory, motivation, and attention"

Potentially a very broad category, which absolutely includes, but is not limited to, stimulants (within a therapeutic dose range). Also, as you can see on the same Wikipedia page, there is an entire category of nootropic stimulants, including the widely used caffeine and nicotine.

Ah, thanks. Only had Adderall once, and it didn't feel the same. Modafinil had a much more subtle effect, with few downsides (just don't overdo caffeine while on it).