Sources of knitting patterns for adult slippers include AllFreeKnitting.com, KnittingPatternCentral.com and KnittingHelp.com, as of 2015. Additional patterns and resources for knitting adult slippers are available at FaveCrafts.com and KnittingPatternsGalore.com.
AllFreeKnitting.com provides a free beginner pattern for a simple knit slipper that is appropriate for any skill set. The pattern mostly involves medium weight garter stitch with 16 to 20 stitches for every 4 inches.
KnittingPatternCentral.com features a number of links to downloadable and printable slipper patterns, including chunky slippers, lightly felted slipper socks, fuzzy cuff women’s slippers and Adirondack’s slipper socks. Some patterns are in PDF format, and some may require site registration before downloading.