General plugins (Local): Question bank unused questions
local_unusedquestions
Maintained by 
Ray Morris
Ray MorrisExtends the Moodle question bank to find questions which are / are not used in a quiz.
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Extends the Moodle question bank to find questions which are / are not used in a quiz.
This may be useful when adding questions to a quiz - no need to add questions which are already in the quiz.
It may also be useful to determine if some questions should be removed or moved, since they aren't being used.
Useful links
Screenshots
Contributors
Ray Morris (Lead maintainer)
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Couple of things you might want to think about
1) The description and screenshots you've added here don't really do the plugin justice and I had to install it to understand what it really did.
2) in lib.php function init() there is a call to global $DB but $DB isn't used.
3) in lib.php $this->onlyused is set in the _construct() function but it is undefined at the class level, you might want to add a "protected $onlyused" at the top of the class or something similar.
4) You may want to improve the phpdocs a little - running it through the automated check tool at:
https://github.com/moodlehq/moodle-local_moodlecheck
The only really important item in that list is probably 1) above.
great work!
Works like a charm on Moodle 3.5