I like the red dingo tags. They have several designs/colors to choose from and they are a bit heavier than the run of the mill tags. Plus if the engraving ever wears off, they will re-engrave it for free.
I have seen some very unique tags on etsy.com as well. I think Ollie might be getting one of these in his stocking:https://www.etsy.com/listing/9980919...=dog+tags++bar