Darnold and Herndon are the only two that even have a remote chance of breaking out, but even that is pretty unlikely from what we've seen so far. The others that have been mentioned? No chance. Most likely scenario, though, is that there aren't any players on the current roster who will have breakout seasons either in 2019 or beyond.
Referring to an incident I saw at a game earlier in the year. He may have just been closing his eyes to regain focus, but it sure looked as if he were sleeping.