As of November 2015, some free online knitting patterns for slippers are Grandma's knitted slippers, basic chunky slippers and cozy slipper boots. At the Fave Crafts website, Grandma's slippers come up low on the foot. They require two skeins of yarn and use U.S. size 10 knitting needles.
All Free Knitting's chunky slipper pattern uses just the garter stitch, so it is simple enough for beginners. The top of the finished slipper reaches almost to the ankle.
At the DROPS Design site, the slipper boot pattern goes well above the ankle. The cable stitch around the top of each slipper is decorated with three buttons.