Just a thought, but if the tag is important enough to be used for this kind of categorisation, wouldn’t it also be natural to have a page for that tag, and use that as the base note for your graph?
I’m mentioning this as I’m contemplating my usage of tags, and whether I should use an extra tag to identify this reference as the identifying definition of use of this tag.
So given a lot of pages tagged with #mytag, then only one of them either had the extra tag of #id (or #definition), or if one would like to use nested tags, one could use #id/mytag. Now you could give pages with the #id tag a special color as if they were a tag node, since in essence they’re the originating point for that tag.
I am happy that you have requested the feature I am missing in Obsidian.
Since you have already posted, I don’t need to post again.
@holroy This feature would make it easier for some users to maintain a zettelkasten system as you won’t have to create separate notes as hub notes. And who knows, maybe there are other use cases of this feature that we are not aware of it yet.
Whether this feature has a valid use case or not, I think it would be natural for the graph view to show only “Mentioned Tags” from the filter section.