I bought this pencil case a few years ago and I LOVE it.

https://www.amazon.com/gp/aw/d/B07KVWNJT4?psc=1&ref=ppx_pop_mob_b_asin_image

It has additional "pages" you can attach/detach using velcro.

I have 1 page of loops set aside because I haven't needed it yet, but if I buy more hooks, I won't have to upgrade my case yet.

The only downside is that it's kinda big, so I have this case for all my crochet stuff to live in, and then use a smaller notions pouch for individual projects.

Edit: THEY HAVE WAY CUTER DESIGNS NOW! Mine is plain grey, but they've got unicorns and some Lisa-Frank-looking-pineapple-thing going on. I kinda want a new one, but mine has been standing up so well, I don't need it, lol.