Shark Tank, American Ninja Warrior, and America's Got Talent are the only reality shows that I make the effort to watch. Back in the day I was also a fan of Fear Factor, which was one of the first reality shows, IIRC.
I don't get cable but if I did, I'd also watch Diners Drive-Ins & Dives. Guy Fieri brings a great energy to that show, and what can I say, I'm a sucker for the kind of comfort food that he usually features. Makes my mouth water every time!
I used to be a fan of Gordon Ramsay, especially back when he was doing Kitchen Nightmares, but his shows nowadays are more about competing chefs, which I'm not as interested in.