More serious? I always recommend the same book first. Peace Like a River, author Enger. Also Extremely Loud and Incredibly Close and The Strange Incident of the Dog in the Night-Time. Can’t recall authors but the titles should be easy.

Nonfiction? The Ghost Map (can’t recall author).

YA? Kit’s Wilderness, can’t recall author.

If you are looking for something a little more serious, I would recommend Lorrie Moore. Her books of short stories (Self-help & Like Life) are brilliant pieces of short prose.