“Cool” is a coveted label that brands across industries are constantly trying to earn. Even the youngest consumers and household influencers—tweens—already have plenty of opinions about which brands are cool. The influencers tweens follow, many of whom are kids themselves, introduce them to new toys, games, clothing, and other products that shape what’s considered cool right now. And of course, friends and classmates play a big role, too, as tweens notice what their peers are wearing, playing with, and talking about. But while some of their picks for coolest brands overlap with those of older Gen Z and Millennials, many...