I looked into it more (mostly to see if anyone is selling them). You can buy ones for Nero, Nico, V, Dante, and Vergil. Either as a full pack (Dante and Vergil) or (Nero and Nico). V is sold all by himself. Nero and Nico have hugging charms you can stick on in their pack too.
And as expected, the price online is disgustingly high.