Suggestion that would be useful for /sell & /sellall would be a feature to limit what can be sold depending on item status.

For example being able to have an option "disable-selling-named-items: true"

Personally this would be a nice change to prevent players selling rares or custom items they don't wish to sell. I've seen other threads of this request when looking into this.

You already have requested this before, that issue is still open. #1988

Closing in favour of #1988.