Call them straps, charms, fobs, or thing that helps you fish your phone out of your pocket or purse; they are very popular with me and other 14 year old Asian Girls:

We work hard for you keeping in mind this words. This does not mean just to sell well phone straps all over the world. We think that one Phone Strap is a tiny toy or pettit [sic] accessory for a person but it has an infinite loveliness maybe he longs for. This is What we are all about. "From Japan to you, we bring Straps to you with Love"

[ Phone Strap & Accessory, StrapYa! Stuff Introduction ]

They have everything from Zippo lighters, to Hello Kitty, to food items, and even miniature cell phones to hang off your your cell phone. I've been surfing for hours in amazement, and looking for a replacement for the "Hula Girl" that Yaty isn't so keen on. I found another site that has some coffee related charms, but alas I don't speak Japanese, nor live in Japan.