These, if auto created, come from an agent. I inadvertently turned on “Use collection info from The Movie Database” in the Movie Database agent settings. This created a bunch of collections I didn’t want on many of my 2700 movies.
I found I could delete all the collections association in the taggings table but then I would have to rebuild all the collection i previously had. I settled on deleting any collection than had less then 3 members with this SQL code:
use SQLite or DbVisualizer or the like.
where id in
select tg1.id from taggings tg1
left outer join tags tgs1 on tgs1.id = tg1.tag_id
where tgs1.id in
(select tgs.id from taggings tg
left outer join tags tgs on tgs.id = tg.tag_id
where tgs.tag_type = 2
group by tgs.tag
having count(tg.id) < 3
order by tgs.tag
The tags are in the table tags, you can correct any spelling issues there as well. The association to a movie/media is in taggings table. The above removes the association of a tag to a movie but does not delete the tag itself. This worked well for me and I hope it helps somebody else too.