I would probably say that Formula One was at it's biggest during the 1990's and early 2000's even during the boring Schumacher-Ferrari era..., F1 had lots more manufactures during that popular time like Ferrari, BMW, Toyota, Jaguar, Honda, Peugeot, Renault, Mercedes, Ford, Cosworth, Asiatech, Supertec, Mecachrome, Yamaha, Lamborghini, Venturi, Spyker, Mugen and Lotus.