There are only two rules: under 300 yards of yarn (or up to twice that for stranded colorwork, because after all you’re only knitting half the yardage); and available instantly online so you can cast on immediately. The yardage limit means a project can’t take too long, and increases the odds of your finding appropriate yarn in your stash. Some patterns are free; others cost a few dollars.
Teens and twenty-somethings should find these patterns appealing:
Westward hat or headband from Westknits features garter-stitch/slip-stitch colorwork and Latvian braids; the hat has a cabled crown. The headband would be great for snowboarders. Two colors; 85 yards Aran weight yarn for headband, 150 yards for hat. Mix ‘n match hats by Amy Anderson offer lots of options – 3 sizes for toddlers to adults, 2 colorwork patterns, earflaps or not, rolled or picot-edged brim. 200-220 yards DK weight. For those who like their hats slouchy – the bold Mondo Cable Cap (Ravelry link) from Chic Knits in 190 yards of worsted or Aran yarn.
Some girly possibilities:
Blomst mittens have a mod-Scandinavian look. 250 yards total of DK yarn. There’s a matching hat as well. Fishnet anklets in spiraling lace mesh (free; Ravelry link) from the Purl Bee use just 185 yards of fingering-weight yarn. There’s a bit of a steampunk vibe to Ysolda Teague’s Lace-up Opera Gloves (free; Ravelry link). 140 yards worsted weight yarn (hers are in alpaca/silk) and 4-5 yards of satin ribbon.
Twilight-inspired Team Swiss or Bite Me fingerless gloves are knitted in one color and embroidered with duplicate stitch. Multiple sizes; 120-130 yards sport-weight yarn. Simple ribbed Potter Mitts (free; Ravelry link) in Hogwarts house colors, fingering-weight yarn. We Call Him Spidey mittens (free; Ravelry link) are sized for toddlers; 150-200 yards fingering weight. There’s also the We Call Him Spidey hat (free).
For small ones:
Milo seamless top-down vest is written for DK yarn in 11 sizes from newborn to 6 years. 130-300 yards for sizes 0-3 years. Would be great in handspun; you could easily work it at a different gauge, using the numbers for whichever size will give you the right measurements. The Shrug Bug jacket is also top-down and seamless; one size for babies 6 months – one year, 60-80 yards super-bulky yarn. Laura Nelkin’s Leg Ups legwarmers (free; Ravelry link) are worked in bicolor brioche stitch. Five sizes for babies to adults in worsted-weight yarn. Teens might like these too.
Something to play with?
Elijah stuffed elephant by Ysolda Teague is seamless, with hardly any finishing. 218 yards DK yarn, 10” tall. Gnome Babies (free; Ravelry link) use about 25 yards of yarn and may be knitted at any gauge – great way to use up leftovers. The irresistible Estonian sheep puppets were originally published in Spin-Off magazine. Various colorwork patterns for the body; about 90 yards laceweight yarn in each of two colors – or could be knit with fingering-weight yarn.