Much of my pattern inspiration comes from textile prints. I found a used copy of the V&A Museum’s “Thirties Floral Fabrics” book on amazon.
I love to see the colors the textile designers chose, how they abstracted the flowers, how they used brush and pen strokes to capture the essence of the flowers. My favorite pattern of this book is the one on the cover. I love the wavy shape of the petals and the blue accent color. I’m not even sure what kind of flower it is!
See if your library has books on textiles and page through to collect inspiration. You can also visit the V&A Images website, which has some great textile and pattern images from their collections: https://www.vandaimages.com/collections.asp?cat1=Patterns+and+Designs&cat2=PatternsAndDesigns