What effects exactly are you looking for?

Energy? Focus? Is it for school or more for stuff like working out?

Noopept gave me a pretty noticeable stimulant / energizing effect, almost too much at times. Just watch out for irritability or changes in personality.

You'd probably like the effect of adderall the most, but IDK if I'd open that door at your age.

There's also modafinil, it has a strong stimulant effect somewhere between coffee and adderall. I'd guess that's most similar to what you may want.

Psychedelic mushroom micro-doses can give you a lot of energy, and it's more holistic than the narrow, sharp energy you get from caffeine. It's also incredible for mood and creativity.