Although it is not a compact handset, the new ZTE Nubia Z18 also carries the "Mini" attribute. This 5.7-inch handset is powered by the Snapdragon 660 processor, next to 6 GB RAM, as well as 64 GB or 128 GB internal storage. Sadly, it is only available in China for now, where it can be acquired for the equivalent of US$285 or US$335 (depending on the amount of storage).
https://www.notebookcheck.net/ZTE-Nubia-Z18-Mini-debuts-in-China-with-a-5-7-inch-display-Qualcomm-Snapdragon-660-processor.298664.0.html