An average knitter would have built up a selection of knitting needles in different sizes, so a carrying case to keep all of it in one place will be appreciated.
An item knitters love to use is the yarn holder. So your yarn isn't running all over the place and gets protected from dust. A handle allows you to move it around conveniently.
A knitting bag to put all your knitting items in. I have one for beading, gift wrapping and even sewing. So one more for knitting to keep your stuff organized. Also handy for crafting parties.
A yarn holder and knitting bag in one, it gets even better!
Subscription to a knitting magazine or knitting pattern book to try out all the new designs and patterns. Great for beginners as we always need the inspiration.
Cushion inserts for making huggables. You might want to consider microfibre fill for making soft toys as well.
Specialty cleaning solution to care for your handmade knits. I know you definitely need special detergent and settings on your washing machine for homemade knits and not everyone has such things in their home.
Non-slip latex to make your home knitted socks non-slip.
Liqui Sew is a permanent fabric glue to bind the ends down and together.
Fray stop to prevent the edges from fraying, an alternative to sewing the seams down.