I'm really paranoid about what I put in my hair, but France Luxes has some tiny tige boule barrettes that are very gentle on hair and work really well for what you want. They won't hold a whole lot of hair, but I find this actually works better, because they don't mess up curl pattern. They only come in colors, but they're pretty subtle.

France Luxe Mini Volume Tige Boule - Barrettes - France Luxe Accessories
Originally Posted by CurlyInTheFog
Holy cow! I've been lamenting the lack of pretty barrettes but wow. There are some pricey barrettes on that site! And $24 scrunchies!