Almaborealis founder Maija Nygren took cues from early learning theories, such as loose parts play, to design a tactile kit for children aged four to 12 that encourages them to make their own clothes.

Twice a year, the designers at kids-clothing label Tea Collection hop on a plane to a new corner of the globe—recently, it was Peru and Japan—in search of inspiration. The next season, onesies might ...