Knitting accessories can be purchased separately. If you are new than just get a basic kit like the Clover Knit Mate above, you will definitely use everything in it once you get started on knitting.
Point Protectors are caps for your knitting needles, so you don't accidentally poke anything with it. There are larger caps for multiple knitting needles.
Stitch Gauge that allows you to see the size of the stitches and the size of the knitting needle. Yarn size has to correspond with needle size. Patterns and yarn balls usually carry instructions on what size needle to use and stitch size.
Stitch Markers identify the areas a twist, switch or colour change is required. Martha Stewart looms have different coloured pegs for the same purpose.
Stitch Holders come in all shapes and sizes. It basically holds your stitches while you complete the rest of the row. Commonly used in cabling or when knitting rounded corners like gloves. This particular clover version allows you to slide stitches over to the other side easily.
Measuring Tape is an essential tool in any craft project. Used to measure 2 pieces of knitted fabric that are to be matched up or how many more knitted squares are required for a quilt.
Row Counter is a really useful tool, right now I make notations on a piece of paper after each row.
Tapestry Needle to weave in the loose ends and to sew 2 pieces of knitted fabric together.