As far as I'm aware, there's no black jewellery items for the pendant / glass shards. Personally, I'd love to see them as some current colours just don't really suit particular lions.
Ideas I sketched up (bare in mind Lioden artists will do a better job lmao):



I know the current colours are based off crystals, so perhaps they could be made out of tourmaline, obsidian, or even blue goldstone!



If you know anymore "jewellery" type items that you want in black also, let me know in a post below!