The list really isn't too long. The Big Ten is planning on going to 18 or 20. You could pretty easily narrow the candidates down to BC, UCONN, Syracuse, Notre Dame, Virginia, North Carolina, Duke, Georgia Tech and Florida State (if they make a strong enough case). That's basically eight or nine teams for a maximum of six spots unless Texas were to decide to join (in which case Texas and Kansas could be candidates).
It's almost a guarantee, though, the Big Ten will wind up with at least 18. They're only stopping at 16 if it is the right two schools, and I don't think the combination of schools they would ideally like to get with 16 will happen unless they topple more dominoes.
I could envision a scenario where the Big Ten went after BC, UConn, Virginia, UNC, Georgia Tech and Notre Dame. You'd have an Atlantic corridor that stretched from Boston to Atlanta and westward to Chicago/Minneapolis with most points in between. The two things that could change that scenario are whether UNC insists on Duke (not that they wouldn't fit the Big Ten profile) or whether FSU convinces the Big Ten it's committed to becoming a viable research institution. Obviously FSU would be cherished if that happens given the strength of the football program and the location within a heavily populated state.