I voted for Harris, Sermon, Gainwell, and Stevenson.
Harris is a slightly better prospect in a much better situation.
Sermon is in a much better situation, and while I prefer Carter as a player. Every RB with a pulse has succeeded in Shanny's offense.
Gainwell is a slightly bigger talent than Hubbard, but CMC is pretty locked in. While I doubt it will happen, its possible Gainwell can push Sanders at some point.
I like Herbert more as a player, but he's pretty buried right now. Also has more competition going forward, as Michel is likely out of NE soon.