What are the best websites for knitting/crochet yarns?

[Spliffle]

I'm trying to find a wide range of metallic crochet yarn & not having a lot of luck.

Black sheep wool is my go to

I use Etsy for special ones like metallics, they have tons - they can be really expensive though.

Try Wool Warehouse, they have a lot of stuff

Have you tried Hobbii metallico