Shorts/Shortalls are always a nice go to. Tykables cargo shorts are too cute and very passible in public, but they have the buttons on them so you can change your diaper!
Striped shirts, plain/printed tees are good choices to go with. Even short sleeved onesies could go very well with them!
I like plain socks most of the time, but longer printed socks always make me feel little.
Velcro/slip on shoes are great too and can be fashionable as well! Also Babylock has the right idea - light up shoes are cool no matter what but they can be hard to find.
You can always get childrens backpacks and use them anyways, or you can get mini backpacks!
I also like hats a lot - tight beanies, baseball caps, those silly cartoon hats, etc