I think some good names have been put forward thus far, and I tend to agree with a lot the suggestions for those who never made it onto the grid, such as those who never passed the pre-qualifying phase.
There are a few others I would like to mention though:
Bernie Ecclestone. A lot of people tend to forget he tried to qualify for a Grand Prix once (1958 Moroccan Grand Prix I think), but he was slowest of all entrants and did not qualify.
Toshio Suzuki (no relation to Aguri as far as I know). Replaced Alliot at Larrousse for the last two races of 1993, and while he finished both of them, he wasn't exactly noticed.
Miguel Angel Guerra: Made the grid just once for Osella in 1981, and promptly crashed and broke his ankle. He was never seen in F1 again.
Jean-Marc Gounon: His outings for Minardi and Simtek don't exactly stick in the mind.
Oh, and I strongly agree with the contributor who suggested Tomas Enge. His outings for Prost in 2001 were pretty unremarkable, save for a big crash in practice at the Japanese Grand Prix.
My favourite teams: Minardi, Forti, Osella
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