Right now, it seems inevitable that it'll four of Alabama, Clemson, Ohio State, Notre Dame, and Georgia. However, I just have a feeling only two-three of those are going to get in. We've seen it happen year after year where teams in really good spots just slip up or choke down the stretch. If I had to choose three of those teams to slip up, I'd choose Notre Dame, Georgia, and Clemson. Notre Dame really shouldn't lose any of their remaining games, but Brian Kelly has found ways to lose games when his team has looked great in the past. Georgia has a difficult schedule coming up, and I think they're a noticeably worse team than Bama at this point. Clemson looks good, and like ND, they shouldn't lose another game on their schedule. They've lost to much less talented teams in the past two years, and I think a bad loss could sink them this year (2016 Pitt, 2017 Cuse). I also don't feel great about Ohio State, and I think they could easily slip up too.
If I'm making a bold prediction right now, I'd pick Alabama, Ohio State, Notre Dame, and NC State. I really just don't want it to be Bama, Ohio St, Georgia, and Clemson because that would be boring.