Pillows are a great way to showcase crewel embroidery, like this project from New Crewel: The Motif Collection. I used the colors of Appleton Crewel Wool recommended in the book, and Saral Transfer Paper to trace the patterns onto the fabric.
The white pillows are fronted in linen twill (color oyster white) and backed in orange and white geometric fabrics I purchased here; for the blue pillow, I used linen plain weave (color dark turquoise) for both front and back). The larger pillow is 14″ square, and the smaller two are 12″ square.
If I wanted larger size pillows, I would do a pattern repeat like the 14″ one here – you could enlarge the dainty doily pattern easily enough, but a larger hollyhock pattern would mean a larger area to cover with satin stitch, which is time-consuming, yarn-consuming, and doesn’t look as good on a large scale.