Susan, a novel, (1809) author unknown, was published in 1809 by J. Booth. Scholars surmise that the appearance of this novel spurred Jane Austen to write the publisher Benjamin Crosby, who had purchased the manuscript of her novel Susan (the gothic spoof which was finally published as Northanger Abbey), to ask him, when was he going to publish her novel? He, or rather his son Richard, replied that they owned the manuscript, they were under no obligation to publish it, and she could have the rights back by refunding the ten pounds she'd received for the manuscript. The matter rested for a few years more until Henry Austen, Jane's brother, paid the ten pounds and then informed Crosby that the manuscript he had spurned was by the author of the well-received novels Sense and Sensibility and Pride and Prejudice.
So we might expect that Jane Austen at least looked at the novel Susan. She also changed the name of her heroine from Susan to Catherine.
But first, let's look at a novel which we're pretty sure Austen read, because she joked about it in another one of her letters: Margiana, or Widdrington Tower (1808), by Mrs. Sykes.