When Bitty started kindergarten, we had a goal to get him to wear something other than just his Thomas shirts. After all, with two older brothers he had a decent collection of nice clothes that he wouldn't wear.
We made a "rule" of wearing horse shirts (polo, for whatever reason he likes the horse but wouldn't wear any of his other brand shirts) to school and saving the worn out Thomas shirts for home. And it worked :).
By the end of the school year, he had developed a fascination with his favorite color - pink, at the time - and wanted to wear his pink polo shirt every day. Due to laundry conflicts, we convinced him that red was "kinda like" pink and he had several red shirts so almost every day of the week he wore either pink or red (with the occasional green when pink or red were unavailable).
Over the summer, his favorite color changed to red. We made a new "wardrobe" goal for 1st grade - to expand the possibilities of "acceptable" clothing to include colors other than red, pink, or green.
Whenever he wore pink, he called himself "Kirby". Then he decided that his pink shirt was Jigglypuff , and his red shirt became his Kirby shirt (Kirby wears red shoes, and I'm guessing he wanted his favorite color shirt to be named for his favorite character).
And that gave me an idea - because as is so often the case, "our" ideas really come from just following his lead :).
Bitty is increasingly into Pokemon these days (autism hasn't prevented him from wanting to do whatever it is his big brothers are doing, lol), so I figured if the pink shirt could be Jigglypuff, then maybe I could get him to wear his yellow shirt by calling it Pichu.
It worked :). That opened up all kinds of possibilities... after all, there are hundreds of different Pokemon, with characters of all colors, so if we could expand the Pokemon color-coded shirt thing, we could get him to wear pretty much anything in his closet.
So now we have:
(I know, a couple of those aren't Pokemon but they are among his favorite video game characters).
When it's time to get dressed in the morning, I just ask him which character he wants to "be" that day and he chooses the corresponding shirt color. Or some days I might suggest a character. It's great from a pretend play perspective, and I love seeing him wearing more of his clothes. I also love that sweet little smile when I ask him "are you (fill in the blank) today?" and he proudly nods.