I wouldn't think there would be too much to choose from out there, but there is!!
what kind do you have??
I used to have the machine engraved ones, like you get at the local big box pet store, but I found that they end up wearing down pretty fast! the engraving isn't that deep either. It leave them really hard to read and stuff rubbed off on light colored coats :(
I've seen those little plastic ones, that aren't supposed to make noise, but I haven't tried them. but one thing I don't like is the connector piece on those is plastic! gah. I'm sure it can be changed out, but nothing plastic lasts on my dogs!! LOL
Lately I've been making my own, hand hammered letters etc. Zoey has already lost one tag, so it's nice I can just make her another in ten minutes.
No fun shapes though, just a regular old circle. lol