The debate exists amongst clinical pharmacologists as to unlimited supplies of which drug would be most useful when stranded on a deserted island. The tricyclic antidepressants have always rated highly because of their variety of useful therapeutic effects, but valproate also deserves to be high on the list. Of course, it will protect against seizures, if they arise, but it could also be useful for analgesia, preventing migraine and stabilizing the mood particularly if one becomes mentally unbalanced on the island. It might even help to prevent the development of cancer.
Peterson, G. M., & Naunton, M. (2005). Valproate: A simple chemical with so much to offer. Journal of Clinical Pharmacy and Therapeutics, 30(5), 417-421. https://doi.org/10.1111/j.1365-2710.2005.00671.x