Fark,I don’t know mate. I just know from some of your posts, that basically anything with an engine in it, you’re a fan.
But seriously, just to answer the question.....
F1 - Any Aussie driver / McLaren. When growing up I was a fan of the wee frog as Sir Jackie Stewart called him...Alain Prost. Also a fan of Ayrton Senna and Fernando Alonso, but couldn't stand Schumacher. Being from Adelaide I was lucky enough to see a lot of the greats live when the AGP was here (another reason to hate Melbourne).
Touring cars - Always a Brocky fan regardless what his personal life was like, but learned to appreciate others as I got older, especially Allan Moffat. Just not a fan of any of the current mob.
MotoGP - No one in particular since there is no Gardner, Doohan or Stoner right now. Partial to Yamaha though since I've always owned them as road bikes. My current ride is a 1985 XJ900f.
Sprintcars - Was always a Bill Barrows fan (the oldies here who went to the speedway might know who he is lol). George Tatnell too.
Speedway (bikes) - Jason Doyle (a Newcastle boy who won the 2017 World Championship).
Drags - Rachelle Splatt (if you saw her calendar shoot back in the 90s.....you'd be a fan too

). She was bloody quick though (was? Still is. She still races today as well as being a mum of 5). First woman to run 300 mph (482 km/h) in a top fuel dragster.