Vitor Meira
Vitor Meira is one of the single most underrated IndyCar drivers of all-time, and it's a shame he was never able to win at least once. He recorded 15 podium finishes, including eight as runner-up, during his career. In 2006, he finished on the podium in nearly half of the season's races.
Meira, like Hildebrand, is one of the best Indy 500 drivers who never got to drink the milk. In 2005, when all the hype was surrounding teammate Danica Patrick, he actually finished in second place behind teammate Wheldon.
Then in 2008, he placed second again, beginning a streak of four straight runner-up finishes for Panther Racing which included two from Wheldon in 2009 and 2010 and then, of course, Hildebrand's in 2011, which ironically handed Wheldon team owner Bryan Herta's one-off entry the victory.
It would have been fun to see Meira compete at least once in the DW12 era, even if only in an Indy 500 or two. Unfortunately, he never competed again after Wheldon's tragic Las Vegas crash in 2011.