Ideas for chewing alternatives

I have a 3 year old, 60 lb dog who loves to pick up and chew on the smallest objects. She will occasionally chew on appropriate chew toys that I’ve bought for her, but she absolutely loves finding the smallest things (like buttons from clothes, the plastic ends of strings, small, flexible metal) and nibbling on them.

She is very well trained on dropping whatever is in her mouth on command, but then she looks for the next small thing to chew on.

Any suggestions on toys or other safe chewing alternatives that could maybe mimic the satisfaction she gets from chewing small items?

TIA!