Pick a keg that looks clean inside and out, with no labels and that doesn't leave rubber residue on everything it touches. Tie a bow on it, fill it with smaller items, and leave your brewer wondering why the keg is so heavy. Good scale Any good quality scale graduated in either ounces or pounds is a handy item for brewing. For the most part, the same qualities that make a scale good for ordinary use make it good for brewing use, so no brewing expertise is needed to shop for one. Check office supply, restaurant supply and department stores for good-quality scales.
Digital ones are a luxury item, but a wonderful gift nevertheless.
Few brewers buy brand new kegs because they are so much more expensive than used ones. The same practice for purchasing used kegs applies to new kegs for determining the type at the store. If brewing in the kitchen is getting old, consider the gift of a propane burner to move the brewing process out of the house. To help prevent purchasing one that's not suitable for brewing, get this from a homebrew shop instead of a hardware or camping store where you might find it cheaper. If your brewer already has a burner, consider an additional propane tank or two, available at hardware stores.