I have all different clothes for mine but the most important piece of clothing is a nice warm coat for winter. I see that you live in Canada so it is a necessity more than anything. I also have boots because of the salt but they really give me a hard time when I try to put them on.
Then there are all of the bows, dresses, hoodies, sweaters, jammies, coats, tshirts
As for a harness, that depends on what it is we are doing. If I have one is a carries or carseat I like a step in harness. If we are going for a walk I like the step in or the gooday harness. But everyone has a different opinion but we can pretty much agree it is fun to put outfits on them