The FIA World Rallycross Championship might be the motorsport where you get the most wildcard entries. A lot of healthy national championships, and the connection with both racing and rallying makes it a motorsport where a lot of drivers can enter. At Lydden Hill the series saw a record breaking entry of 37 cars in the top class, and some of them were wildcard entries. Two of those ended up in the final; Andrew Jordan and Tanner Foust. In this video they talk about their relationship with WorldRX, and a view on how it is to be a wildcard entry in such a series.
It's really interesting to see these guys talk about this, because I'd really like to see them do a full season in WorldRX. Foust actually says that he would want to do so, and Jordan has been competing in British rallycross before.
The next round of WorldRX is in Hell, Norway 13-14th this month, then Ken Block is one of the wildcard entries along with a huge pack of Norwegian drivers. Watch out for a preview of that next week.