#3 Romain Grosjean
Romain Grosjean was famously branded as a "first-lap nutcase" by Mark Webber in 2012, but the Swiss-born Frenchman has come on leaps and bounds since this remark. Grosjean rapidly improved after being retained by Lotus for 2013, claiming six podiums and regularly being one of Vettel's closest challengers during the German's record-breaking season.
Lotus struggled to adapt to the V6 regulations, but that didn't stop Grosjean from completing some standout drives, including his stunning podium at Spa in 2015. Yes, Vettel's puncture helped RoGro out, but the Frenchman was unbelievably quick that weekend and even he couldn't explain how he got that third place.
Grosjean's move to Haas has given him a new lease of life, although he was out-scored by the next man on this list last year. Grosjean's issue is that he hasn't quite managed to get his consistency together, as we saw during the first half of 2018, but on his day, Romain is one of the fastest drivers on the grid.