Motocross Championship was created in 1994.
Motocross Maniacs happened in 1989.
The prime product developed by Moto Games is motocross video games including Motocross World Championship, Motocross Madness, Freestyle Motocross and X Games.
Motocross - video game - happened in 1983.
Ricky Carmichael is the GOAT (Greatest of all Time) when it comes to motocross. He is the current record holder of the most championship titles throughout a racing career.
The AMA was founded in 1924 but the first AMA professional motocross race did not happen until 1969.
There are many large prizes that a pro motocross racer can win each year. The most notable are the X-Games event gold medals and the AMA Motocross Championship.
Blair Morgan, a multiple time winner of the Canadian Motocross Championship, was born on October 8, 1975. He is currently 37 years old, which quite a lot for a motocross racer.
The link below is as close as I can find, it is not a complete list though.
Unreal Championship happened in 2002.
Championship Pool happened in 1993.
Championship Pony happened in 2008.