I'll soon build one for DMV reviews and they will be supported in NDK.
Hopefully that'll mean that NIP-32 labels will be readily accessible to many apps with a very simple interface.
Nos.social was working on a content labeling one, but the only one I'm aware of is coracle's relay reviews: https://github.com/coracle-social/coracle/blob/master/src/app/views/RelayReview.svelte
I'll soon build one for DMV reviews and they will be supported in NDK.
Hopefully that'll mean that NIP-32 labels will be readily accessible to many apps with a very simple interface.