Very cute buttons. In addition to the size, maybe you could tell us what they're made out of. They look like wood to me. If that's the case, you may not want to put them on a sweater because after washing them a few times, your buttons will be ruined. And you probably don't want to take them off and put them back on every time either.
So maybe a hat, fingerless mittens, or a purse? Maybe something like this hatwise?