Tarō Gomi

"Sheep wears a fluffy jacket...
Goldfish wears a tie-dye skirt..."
But the boy wears...nothing? A naked boy with a surprised expression gets dressed in a blue shirt and green pants on the final page.

About all the things you can learn from your friends. Simplistic language. Both Ms and Mx are indifferent at this point.

English translation by Amanda Mayer Stinchecum

All animals eat, and so all animals poop! Humans are animals and we poop too, though all animals poop differently.

Very sweet, simple drawings in this 1970s Japanese book. Focuses more on the theory of using the potty than practice, so to speak.
I always thought I had read this one when I was a kid, but it didn't seem familiar so I think I actually read Once Upon a Potty.

This is so clever. When sharing this with preschoolers, it's fun to talk about the different meanings of the word "miss." When we miss someone, we want to see them. But sometimes when you try to see someone you miss them!