PrettyGarden Oversized Zip-Up Sweater; $39.99; amazon.com Everlane The Felted Merino Half-Zip Sweater, $145; everlane.com lilima Open Front Zip-Up Cardigan Sweater, $38.99; amazon.com ...

A few months back, we wholeheartedly vouched for fractional zip sweaters as the most important layer for fall. Well, we're now deep into winter, and it's time to take things up a notch. Allow us ...