Clayton Kershaw
Clayton Kershaw is undoubtedly the best player to ever play who was drafted seventh in the draft. Frank Thomas gives him a run for his money, but Kershaw's utter dominance in the regular season for a longer period of time places him a level above the Hall of Famer. The Los Angeles Dodgers selected the southpaw seventh overall in the 2006 draft out of Highland Park High School in Dallas.
Kershaw's senior year was unfathomably great. He had a perfect 13-0 record with a 0.77 ERA. He struck out 139 batters in just 64 innings. Despite being a top-5 prospect among most scouts, Kershaw slid a bit in the draft behind players like Evan Longoria and Andrew Miller. Kershaw ranked as high as the #4 prospect in all of MLB in 2008, the same year he would make his debut.
Kershaw debuted almost 2 months into the season on May 25th, 2008 against the St. Louis Cardinals (ironic). He threw 6 innings, allowed 5 hits, struck out 7, and gave up 2 runs. Kershaw has yet to make an appearance in his 17th season this year, but he has a career 2.48 ERA, he's struck out 2,944 batters, and his 157 ERA+ places him amongst the greatest starters of his era.
Kershaw has 3 Cy Young trophies, a Most Valuable Player designation from 2014, a Triple Crown, a Gold Glove, and 10 All-Star Appearances. He had the best ERA in baseball 5 times during his career. When Kershaw retires, he will be a first-ballot Hall of Famer. He's accrued 79.7 bWAR for his career, and it's likely Clayton will go at least two more seasons pitching since he's still 36.