Possibly my favorite button closure, 20 hole buttons are extremely versatile.
I've found at least five ways to embroider them with a needle and thread (But I'm sure there are more!) They look so different depending on the type and thickness of yarn you use. Doubling up two colors of thread when you stitch them is another way to personalize this button.
Crocheting into them with a tiny hook and some crochet cotton adds infinitely more options for customization. The button above (on <a href="http://www.ravelry.com/projects/katrinkles/keams">Keams</a>, by Taiga Hilliard) was embellished by crocheting one row of two single crochet stitches into each hole. Not only does crocheting around the edge make a smaller button able to work with a larger button hole, but it makes a satisfyingly soft edge for your fingers.
My go to, wear every day cardigan has 20 hole buttons and I love how they don't take away from the sweater here. (The sweater pattern is called <a href="http://www.ravelry.com/projects/katrinkles/hey-girl">hey girl</a>, by Bonne Marie Burns). Add some of the same wool as your sweater to these buttons and they blend in with the garment so nicely.