If the SEC were to be able to draw any schools away from the ACC it should be: Florida State, Clemson and Miami (to replace the departing and unwanted Vanderbilt).
There should be no further discussion.
Florida State and Clemson are the most SEC like in their approach to football. Plus they are the two biggest stadium schools in the ACC which would allow them to compete, dollar wise, in the middle of the SEC.
In Miami, playing in a pro stadium, and offering some pizzazz to the SEC could and would be competitive in the SEC and secure the entire state for viewership and recruiting.
Should Missouri also depart, which I think is logical, the ACC replacement should be Louisville. Rabid football fans with an expandable stadium, top ten baseball, and a basketball program to challenge Kentucky. Louisville basketball would give relevance to Kentucky and Tennessee (since those two struggle and will continue to struggle to recruit SEC caliber football players) in the modern SEC.


Miami, Florida, Florida State, Auburn, Georgia, South Carolina, Clemson, Tennessee
Texas A&M, LSU, Alabama, Mississippi, Mississippi State, Arkansas, Louisville, Kentucky.

West Virginia and Vanderbilt join the ACC to become a 12 team league, and Missouri rejoins the Big 12 to boost them back to 10.

The SEC would be the undisputed king of college football and would routinely place three teams in an expanded 8 team college football playoff.