First question, why are you even trying to find a unique idea? I thought the same way until I was asked by a mentor,
"Look at your desk, how many pens do you have? How many of those are different brands? If they can survive in such a crowded market, why can't you?"
What he meant was that you don't need a unique idea, and thinking so is a fallacy when most businesses are not unique. Clone a business you like and start competing. Competition is good because it actually validates the market. I'd be worrying there weren't any competition actually.