Some sources for free patterns for knitting chemo caps include websites like Headhuggers.org, Allfreeknitting.com and Hugsforyourhead.com. Knots of Love and Brimming With Love offer easy to intermediate chemo cap patterns.
Headhuggers.org offers a wide variety of close fitting cap patterns, like a "hairy" chemo cap to knit with fuzzy yarn. Allfreeknitting.com includes instructions for the Berries Blast Beanie, or for lace edged, ringed or ridged hats. Make the Bobcap or Upcountry Hat from the free cap patterns on Hugsforyourhead.com. The Knots of Love website offers both patterns and tips for choosing the appropriate yarn. Some simple knit chemo cap instructions are also available on Brimming With Love.