OnePlus started off making "flagship killers" at mid-range prices. The brand has slowly moved upmarket but is apparently set to offer a proper mid-range phone again, in the form of a OnePlus 8 Lite that'll be a successor of sorts to 2015's underwhelming OnePlus X.
https://www.notebookcheck.net/New-leak-throws-more-light-on-the-OnePlus-8-Lite-the-purported-OnePlus-X-successor.446154.0.html