Spoonrocket's cars have builtin heaters that keep food warm, only 2 menu items a day, and really quick delivery. If they actually expanded nationwide they'd kill burger/pizza joints, or at least force them to innovate.
'InstaToiletPaper is doing really unique things like drone delivery of toilet paper and a huge selection! If these guys succeed, they'd be out disrupting the $20B toilet paper market, or at least forcing the to innovate.
InstaToiletPaper is a pretty good startup if existed. When you run out of toilet paper you really want it quick. A drone could fly through a small window and it get it to you. You'd pay $10 for a single roll.
Presumably any drone that can fit thru a bathroom window can fly thru a bigger bedroom window.
Already a thing (minus drones).