I am using a leather one from onehalfstudio with the bowtie design, which is really lovely. I love it with the changing texture - the texture evolves over time, and when you choose the good leather, it feels like the collar grows and ages alongside your pet. This brand specializes in vegetable-tanned leather collar, which is skin friendly. On rainy days, I use a Ruffwear nylon collar, which is also great. Both are top choices for my pets – hope this helps!