The Alchemist Who Survived Now Dreams of a Quiet City Life, Vol. 1 (light novel) — Usata Nonohara

A girl out of time, a fish out of water
Alchemists used to be a dime a dozen in the Kingdom of Endalsia, so Mariela was never particularly special. But her skills were put to the test one fateful day when a horde of monsters came stampeding from the nearby forest. In a desperate attempt to escape the horror, the young alchemist put herself in a state of suspended animation that lasted just a little longer than she'd planned-an entire two hundred years! Needless to say, there have been some big changes, and biggest of all: Mariela is now the sole alchemist in the entire kingdom. Her one wish in this strange new environment is to get back her quiet, leisurely, low-key lifestyle!