Here are some kids slippers.
These are simple slippers, made only in small child sizes. They appear at Walmart in 2019 / fall season. As you can see at about 5 bucks, these are reasonably priced. They're modern, with an all over full color Sonic poses print on a black background. They're just kind of basically foot-shaped with an elastic upper edge so it stays on. The interior is made of white, textured fleecy material to help keep feet warm. The bottom has the tough fabric with rubber texture traction.
The fleecy interior is prone to getting dirty quickly, and then pilly if it goes through the washing machine. The best care for a slipper like this is to put it on over socks to help it stay clean and last longer. Wearing socks with it also helps the fleecy stuff keep your feet warmer as well.