She completed several novels and children's books as well as numerous uncollected poems, including a collection of essays called The Pharos: A Collection of Periodical Essays, published in 1787.
Her final publication, the 1801 novel What Has Been, concerns a woman's inability to support her family by writing fiction.
Her second poetry collection, also called Poems (1802), gathered and published posthumously, is mainly composed of sonnets, elegies, and odes.
Some biographies suggest that her first novel was Simple Facts; or, The History of an Orphan published in 1793.
Mathews died of consumption in York in 1802, aged 30 years old.