Here's another pretty exhaustive list of the player pool for 2018
http://www.sbnation.com/soccer/2014/7/3/5864221/potential-usmnt-players-to-watch-during-the-2018-world-cup-cycle
http://www.sbnation.com/soccer/2014/7/3/5864221/potential-usmnt-players-to-watch-during-the-2018-world-cup-cycle