California's contributions to the automotive world - nope, I didn't get on the list, (I am adding myself to it) but Don did with his Garage Style Magazine! So, congrats Don!

Creative Californians lead the world in entertainment, aerospace and automotive, particularly around Southern California, the car culture capital

 Notable car-related firsts and founders:

1919: Car Styling — Harley Earl, Los Angeles (incl. use of clay models.)
1925: Motel — Milestone Mo-Tel, San Luis Obispo.
1926: Kelley Blue Book — Les Kelley, Los Angeles.
1931: Drive In Take Out Restaurant — Pig Stand, Los Angeles.
1930s: Hot Rods — developed around Los Angeles, tested on nearby dry lake beds.
1930:  Art Center College of Design as the Art Center School.

1936: Maurice Schwatz — custom cars. He made the Topper Car.

1948: Road and Track magazine — John Bond, Burbank.
1948: Hot Rod magazine — Robert Petersen, Wally Parks, Los Angeles.
1948: Drive-Through Restaurant — In-N-Out Burger, Baldwin Park.
1949: Motor Trend magazine — Robert Petersen, Los Angeles.
1950: Pebble Beach Concours d’Elegance — Sterling Edwards, Beverly Hills.
1951: National Hot Rod Association — Wally Parks, Glendora.
1951: Custom Cars — George Barris Hollywood custom cars for tv shows, Los Angeles.
1953: Pinewood Derby — Don Murphy, Manhattan Beach.
1956: Go Kart — Art Ingels, Echo Park, Los Angeles

1957: T Bucket  — Norm Grabowski, Hollywood
1963: Dune Buggy — Bruce Meyers, Newport Beach

1968: Hot Wheels — Mattel introduces kids to cool cars via toys
1973: Toyota Satellite Design Studio, El Segundo.
1983: Automotive Fine Arts Society — Ken Eberts, Temecula.
1984: Motor Press Guild — Matt DeLorenzo, San Pedro.
1986: Automobile magazine — David E. Davis, Los Angeles.
2003: Cars and Coffee — Marc Greeley, Bob Cheatley, Newport Beach

2004: Tv reality shows about custom cars — Boyd Coddington
2006: Just a Car Guy blog — me, San Diego
2008: Garage Style magazine — Don Weberg, La Habra.
2020: Modern Rodding magazine — Tim Foss, Brian Brennan, Fullerton.

Peter Aylett (Laguna Nigel) founded Car Art in 2002 in Southern California he is the great-grandson of a London carriage maker, and during his 25-year career as an automotive design engineer with Ford, Lotus, Mercedes, GM, Nissan, and Mazda, he helped create concepts like the Corvette Stingray III and production cars like the Esprit, De Lorean and RX-8.

Von Dutch and Ed Roth, maybe they should be included, selectively then based on your first comes makes the list for one category, unless you categorize them differently. 

For all I know you might think Ed Roth and Barris are the same category, but when I think of Roth, he was not in a category because of the monster shirts, and comic book marketing, and airbrushing the shirts and sweaters at car shows, plus the Choppers Magazine, and not just the singular focus on wacky custom cars.

Barris started as a reporter for Hot Rod, then customized cars for celebs - unlike Roth who made cars, for car show wins. 

Who invented flame jobs for hot rods? Two Red Lion Special sprint cars in 1934

Von Dutch certainly was not in a category with anyone else, though he did teach others like Jeffries to pinstripe, he was certainly the originator, and his contributions to hot rodding include the invention of lace paint - though Watson took that and popularized it, and Von Dutch got to working with helmets and did the design for the stars and stripes that was copied for the tank of Easy Rider's Capt America bike. 

Also, Norm Grabowski who invented the T Bucket was also the one that created custom shifter knobs. But, that T Bucket - that was pioneering a trend. 

Mr Jalopy invented blogging about car stuff. 

Max Bulchowsky for putting hot rods into GP racing with Ol Yaller

Gene Winfield, not just for the fade paintjob, but also for making Hollywood movie vehicles

Pete Chapouris hot rodding revival in the 70s

Bruce Crower

Cal Club plates

Joe Bailon for inventing candy apple red paint