Muppet Racemania (psx) was the most complete karting game ever made by a long shot.
Bahamut Lagoon (snes) was an amazing Square tactics rpg that just never seemed to have much of an audience.
I don't think Colonization was quite obscure or Penny Racers quite A-quality but I want to mention those too.
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Smurf, the cream of Sonic fanboyism