Has this feature been created? I've seen a couple other threads that have cumbersome work-arounds. I would like such a feature as well so that I could periodically check for duplicate/inconsistent tags.
No. But one perhaps obvious and one hopefully less obvious suggestion on how to get there:
1. You're aware that you can just see all tags in the tag selecter in the left panel, right? And that you can resize that to take up large parts of your screen?
2. Have a look at the Zutilo plugin: https://addons.mozilla.org/en-us/firefox/addon/zutilo-utility-for-zotero/ which will let you copy all tags of all selected items (which could be all items) to a list.
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1. You're aware that you can just see all tags in the tag selecter in the left panel, right? And that you can resize that to take up large parts of your screen?
2. Have a look at the Zutilo plugin: https://addons.mozilla.org/en-us/firefox/addon/zutilo-utility-for-zotero/ which will let you copy all tags of all selected items (which could be all items) to a list.
Also, actually duplicate tags are impossible.