Tabcorp is an Australian Wagering Company that offers real-time horse racing APIs: https://studio.tab.com.au/
Others are a little less public and you need to sign up with an account and prove you are a syndicate. Hong Kong Jockey Club, UniBet, Amtote.
I don't normally talk about this history as I was active in this industry until four years ago. There are however people who have come out in public:
Bill Benter: https://www.bloomberg.com/news/features/2018-05-03/the-gambl...
Jelko: https://www.smh.com.au/national/meet-the-joker-the-australia...
Most of the other families and players are extremely private or are of Eastern European I wont talk about them publicly.
This is a list of common bet types that are targets for these types of players: - Trifecta - Big Six - Quadrella - First 4
Here is a blog on working the combinations of the Big Six: https://practicalpunting.com.au/pp-online/a-z-of-betting/exo...