I currently run the Antique Pattern Library (group and website). If you can find an image on our website ?that appeals to you, let me know. Nearly all are free for noncommercial use. We watermark them but for a cover image I can share one without watermark.
Best wishes,
Sytske Wijnsma
Library Director of the Antique Pattern Library, a project of New Media Arts Inc., a charity registered in the USA.
Antique Pattern Library - Sytske