I know, I know - Halloween isn't even here yet, but holiday Advent calendars are back on Amazon's virtual shelves, and they're bound to sell out before November. If you love the countdown to Christmas and want to enjoy little treats (let's be honest, who doesn't?), consider picking up an Advent calendar ASAP. From makeup to sweet treats, I compiled my top 12 picks to ensure there's something for everyone. See one you love? Don't wait to add it to your cart! These popular Advent calendars commonly sell out before Halloween. 12 Advent Calendars Bound to Sell Out Before Halloween 1.