Yes! We offer Add-on Zip Sheets as separates. They are all interchangeable (within the size) so you can mix and match fabrics and colors! Please click this link to find Add-on Zip Sheets: https://quickzip.com/collections/zip-on-sheets
For example - feel free to add a cozy, warm flannel zip sheet - it will fit on your existing base in the same size purchased with your sateen or percale set.