One thing I've been seeing on Instagram lately is toddler girls wearing romper pants with a crop top, it is really bleurg.
Other than that I dislike character/themed clothes, sports team clothes, sports stuff, too sparkly, too fussy/frilly, light up shoes.
I get comfy pants from gap for the DSs, marketed as joggers but they're normally plain grey or navy in a jersey (?) type fabric, the do shorts as well and then lined ones for winter. Great for lounging around the house, and perfect for nursery where they are still napping, very comfortable. I do like the scandi ones though, they'll do a colourful stripe pair for interest. I also like most of the scandi clothes, it was a great shame when Nordic kids closed down.