Collars are really no appropriate for rabbits. Rabbits don't need to wear tags. A collar can get caught on something, even a foot, and that can panic the rabbit causing serious problems. A decorative collar for a photo is about as far as you want to go.
A harness can be more appropriate, but even then there can be issues. A harness should not be left on a rabbit. Some rabbits won't wear a harness. A few types can be dangerous for a rabbit due to being all one strap, too thick, or not fitted right so the rabbit can slip out.
If you are looking for ID, a tattoo or microchip is a better option. If you want something so you can take your rabbit outside, an x-pen is safer and allows more freedom to move around. If you can't set up a pen or don't have a safe yard, then a harness can be used.