Looking at his Instagram i think also Tom Boonen has switched to some Motorsport competition.
He became champion this year in the Benelux Supercar Challenge, racing for the Deldiche Team. He's actually talented for this kind of sport as well, but that's not really surprising. I wonder if he'll try leagues and cars with greater reputations.He has indeed, he's even on DriverDB. He's done mostly stuff like TCE, which is a semi-pro endurance category, but he's also entered the NASCAR Whelen Euro series. He had a pretty bad crash in October, though, and hasn't raced since, so I don't know how much further he's going to take it.
He's also in cooperation with a few brands, one of which is the La Passione Cycling Couture (who are producing Movistar's new outfit for example).
You can see he's still very much in shape. And hello, Muur van Geraardsbergen.