Lumen Learning/Course HeroLumen has a collection of high-quality OER that can be used as-is or modified to fit students’ needs. The OER in the catalog are free, but Lumen also offers additional courseware for a fee. As of summer 2022, Lumen is transferring much of its course catalog to Course Hero, a homework help site, which, at least for the moment, continues to offer the material for free.