From [this source](https://www.medscape.com/viewarticle/780334).

* Coffee, tea, colas, energy drinks
* Fioricet®, Cafergot®, NoDoz®, Excedrin® Extra Strength
* Plants: Guaraná, Yerba Maté, Cola nut (Kola nut), Cacao, and all the coffee/tea plants.

Since raiding abandonded stores (after the apocalypse, right?) what's left is growing your own.