The Xperia XZ1 Compact was the only true compact flagship of 2017. The device launched with an MSRP of US$600 but is currently available for just US$399.99. Not a bad deal for a last-gen flagship with excellent cameras, Android Oreo, and a headphone jack.
https://www.notebookcheck.net/The-Xperia-XZ1-Compact-is-now-available-for-US-399-99.293550.0.html