midlist

Unlikely to be more than modestly successful.

He scoffs at the lesser-known, midlist and emerging authors […].

Expected to achieve sales performance that blends frontlist performance with backlist performance, being neither a bestseller when new nor a perennial backlist performer but strong enough in each of those categories to be successful overall

The celebrity tell-all has been proposed as a frontlist title, whereas the cookbook has been proposed as a backlist title and the food history book as a midlist title.