Although it looks like Texas and Oklahoma are definitely off to the SEC, expansion may not go much further, at least right now.
The Big Ten doesn't look too interested at the moment and it doesn’t appear that anyone is going over to the SEC from the Big Ten (there were rumors about Michigan and Ohio State but apparently not). ACC teams have signed over media rights through the 2035-36 season so that makes it tougher to raid the East Coast.
It doesn’t mean it’s impossible of course, but the most likely candidates, Clemson and Florida State, would not only have to give up their media profits, but also remember this: Clemson has gone 111-14 since 2012 and has been a consistent presence in the playoffs, winning two national championships and playing for a third.