If you've never searched for this, there are TONS of scrapbooking monthly kits, but very few designed for card makers. Most of the card kits I found are kits to make specific finished cards, rather than leaving things to your design delight.
In December, Northridge Publishing ran a promotion giving you a free extra kit (turned out to be 2 kits!!) if you bought Studio Calico's monthly kit for December. I wasn't sure that I loved Studio Calico, but I figured it was worth testing out. I had so much fun that I subscribed starting this month!
So here are some pics from cards I made with those new kits. Lesson I learned: be willing to try new things!! You might find another addiction... ;-)