You can't have enough knit tops, can you? And after so many plain vanilla scoop necks and v-necks and the like, it's time to start searching out some interesting neckline variations. I just finished this lightweight, heathered sweater-knit top, using my TNT (that's tried-and-true for you non-sewers out there) knit top body and the collar/neckline from Vogue 8497, a trio of Marcy Tilton tops. You can read about my assessment of this particular collar on Pattern Review.
The method for grafting a different collar or neckline onto your basic top is simple: align the center front and the waistline of the pattern whose neckline you want to use with your TNT pattern, then trace a new pattern using both. It can get a bit more complicated, as in this top below with the pleated neckline, using a Vogue dress pattern, 8663. In that case, I made a trial bodice front out of some leftover knit, just to make sure it worked. A little extra time but worth the extra effort to prevent an unwearable top and lots of aggravation.