As a knitter also, this would be my suggestion. I don't buy any yarn unless I have a particular pattern in mind. That's a very personal choice depending on tastes and knitting ability.
What I would like if I got a gift like your making is to get a pattern book with washcloth patterns and then have a selection of different colors, all cotton, Sugar and Creme, or Peaches and Creme yarn, which is specifically for washcloths. They are not expensive and most times they are on sale at Michaels or JoAnns. Get set of needles and crochet hooks for the size needed. Usually US 7 or Crochet hook G. Have fun picking out your gift. Lucky person to get a thoughtful gift like yours!