Primarily NASCAR and any form of short track oval racing, but I watch most F1 races, and watch BTCC, WTCR, and SuperGT when they’re available to watch online. I really enjoy all three of those. And I try to watch whatever Rallycross that I can, I followed Global Rallycross before it went bust.
I watch the Indy 500, and the Daytona and Le Mans 24hs every year but I can’t get into Indycar normally and I’m really not a fan of multiclass racing (SuperGT is the exception). I like all the cars on track to be racing directly against each other.
Only go to oval racing live, would never go to any event where you can’t see the entire track.