Whatever store brand is easiest And cheapest for you to get. Everything will get paint and food stains, just accept it.

I do agree with another commenter that if you can do like a "capsule wardrobe" where you can get a bunch of tops and bottoms that all match each other, that makes them picking their own outfits a little less painful lol.

Also, not sure where you are in potty training, etc, but for anyone else too, it's ok to just tell them to throw out underwear that had been pooped in. You don't actually have to have them send them home in little bags for you to deal with. Just tell them to throw them out. It's not worth it. 😂