I tried out a number of patterns and realized I could have kept going forever, so I settled on this one.
Pattern: Scalloped Potholder (ravelry link); (archived link)
Yarn: Coats Creme de la Creme (worsted-weight kitchen-type cotton)
They're double thickness; on most of them the backs are the opposite colors as the fronts.
Hook: 4.0 mm (US G)