In recent years (2018 graduate), Lucas Bons of Dublin Coffman was definitely underappreciated. He just happened to be part of arguably the best distance graduating class in Ohio ever, but the dude was a monster.
He did his 2-year Mormon mission after high school and then went on to run a 3:55 indoor mile as a freshman for BYU, so his greatness is now seen, but for some weird reason he wasn't given his proper due when he was in high school.