I'd group a few racing series with different variations. So there would be the main name of the series, but within that series would be sub-categories/individual events.
Best Of British Series
DB5 vs E-Type Battle (5 Races)
British Sports Cars - 700PP, Sports Tyres (8 races)
50s Legends (DB3S '53 | D-Type '54) (3 Races)
Le Mans Legends Series
LMP1 Cars BoP'd 2010-2016 (10 races, ~1hr)
Group C Cars BoP'd 1988-1992 (10 Races, ~1hr)
VGT Series
Gr.1 Racing BoP'd [5 Races]
Gr.3 Racing BoP'd [3 races]
Road Car 700PP BoP'd [3 Races]
Soul. Passion. Italia.
450 PP Italian Road Cars (3 Races) [Maggiore East, Monza Full, Sardegna Road C]
550 PP Italian Sports Cars (3 Races) [Monza, Sardegna Road B, Maggiore West End]
550 PP Italian Classics (Pre 1977) (3 Races) [Maggiore Centre, Sardegna Road A]
700PP Italian Modern Supercars (3 Races) [Monza No Chicane, Sardegna Road A, Maggiore Full]
Tokyo Highway Battles
Japanese 90s cars [2 Tokyo Layouts]
Japanese Classics (anything pre 74) [2 Tokyo]
Japanese Unlimited (Anything goes, fast as possible [3 Tokyo layouts]
Ferrari: Corse Clienti
550PP Ferrari Road Cars [5 Races]
Ferrari Classics (pre-1990 road cars) [5 Races]
Ferrari Challenge Trofeo (488 if it's added, otherwise F8) [5 Races]
Ferrari 430 Challenge (F430) [5 Races]
GT3 Series
GT3 Pan American Championship [7 races ~ 20 min] (Interlagos, Daytona Road, Trial Mountain, Blue Moon Infield A, Laguna Seca, Willow Springs Big, Watkins Glen Short)
GT3 Asia-Pacific Championship [7 Races ~ 20 min] (Bathurst, Autopolis Full, Fuji Full, High Speed Ring, Kyoto Yamagiwa, Suzuka East, Tokyo Central)
GT3 European Championship [8 Races ~ 20min] (Alsace Village, Sardegna Road A, Lago Maggiore Full, Monza, Brands Indy, Barcelona GP, Spa, Deep Forest)
GT3 World Series [12 races ~ 45 minutes] (Have to finish 3rd or higher in 2/3 regionals to enter)
Dragon Trail Gardens, Nurburgring GP, Red Bull Ring, Brands GP, Bathurst, Suzuka GP, Kyoto Miyabi, Tokyo South, Watkins Glen Full, Interlagos, Trial Mountain, Laguna Seca
For all of these you can use any GR.3 car EXCEPT VGTs, BoP'd. The World Champ would require one pit stop for tyres.
Ford Vs Ferrari Redux
330 P4 vs Ford Mark IV [3 races]
F8 Tributo '19 vs Ford GT '17 [3 races]
GT4 Series
To be a little different to the GT3 series, and because of the poor balance, I'd split these by drivetrain except the Worlds.
GT4 FF Cup (5 FF Gr.4 Cars) [5 Races]
GT4 FR Cup (12 FR Gr.4) [5 races]
GT4 MR Cup (7 MR Gr.4) [5 races]
GT4 AWD Cup (8 AWD Gr.4) [5 races]
GT4 World Championship (Any Gr.4) [10 races]
Front Wheel Power
350 PP Road Cars [3 races]
450 PP Road Cars [5 races]
550 PP converted touring cars [8 races]
And some single races/series
Super GT Championship 2008+2016 BoP'd (10 race championship)
Econobox Sleepers (Anything considered econobox) [6 races]
Super Formula Championship [10 races]
Porsche Cayman Cup (Cayman GT4) [5 races]
Modern American Muscle [6 races]
Classic American Muscle [6 races]
Pre-War Battle (Alfa 8C vs S-Barker) [3 races]
1950s Race of Beauty (300SL, 500 Mondial, Abarth 1500, Porsche 356s, Porsche Sypder) [5 races]
Nordschliefe: Green Hell (5 races with varying cars, weather, layouts)
There you go PD, 228 individual races making use of a big chunk of your car list but it's FAR from exhaustive, lost interest knowing they wouldn't pay any attention. Still lots more cars to make use of. They'll just continue drip feeding [Generic Name][PP] races.
