Colts. They were a surprising fringe-top-10 real-world defense last year, and with additions like Justin Houston, I expect that to translate to their D/ST fantasy stats.

They're currently being undrafted outside of super-deep and best-ball leagues, but I have a feeling they'll be a savvy pickup for those who can afford a roster spot to use on a second defense. Their positive matchups are fairly evenly spaced throughout the season (Titans Week2, Raiders Week4, Broncos Week8, Dolphins Week10, etc.) in between the tough ones (Chargers Week1, Falcons Week3, Chiefs Week5, etc.), so they will either be added & dropped constantly, or someone will hold onto them & another defense to use together.