Olivier Panis - 1997
We always like to talk about underrated drivers who could've ended up being just that bit more well known, had some things gone their way, whether they ended up with more wins and a respected championship campaign, or even a championship itself. As for the latter many think of Heinz-Harald Frentzen in 1999, myself included.
A championship ultimately wouldn't have been likely, but the case of Olivier Panis in 1997 is quite interesting. He was driving the Prost Mugen-Honda, as Prost had bought Ligier the year before (where Panis already had quite the resume, a shock win in Monaco in '96 and podiums at the 1994 German, and 1995 Australian Grands Prix).
He scored a podium in Brazil, was running in second in Argentina until mechanical failure, and scored another podium in Barcelona, which could've very well been a win had he not been held up by traffic losing 7 seconds to eventual winner Villeneuve. He had a huge crash in Montreal and missed the next 7 races, but I just find it quite forgotten he could've genuinely been leading the championship by around that stage had some things gone different. A great and underrated driver of the 90s/00s, who unfortunately never quite got the machinery again to show his talent.