If I had one suggestion, it might be configuring your tag tiddlers to provide a list of links to tiddlers with that tag — particularly if the tag tiddler doesn’t currently exist, or doesn’t have any extant text content. For instance, you have a “Planescape” tag, but not a Planescape tiddler: it would be nice to be able to search for “Planescape” and find a hub for all the content with that tag!
You could do this manually by adding <<list-links "[tag<currentTiddler>]" field:"title">> to every tag tiddler, or creating a ViewTemplate segment: make a new tiddler tagged with $:/tags/ViewTemplate and give it the following text:
<% if [<currentTiddler>is[tag]] %>
<<list-links "[tag<currentTiddler>]" field:"title">>
<% endif %>
Or if you’d prefer a table of contents:
<% if [<currentTiddler>is[tag]] %>
<div class="tc-table-of-contents">
<<toc-selective-expandable>>
</div>
<% endif %>
The only downside to using a TOC rather than a simple list of links is that if you have multiple tiddlers with the same caption, they’ll be hard to distinguish in the TOC.
In either case, this method would add a “tagged tiddlers” segment to any tag you’ve opened in the story river — whether or not it’s a “real” tiddler you’ve created. But since a lot of your tags are already well-documented with their own tables of contents, you probably wouldn’t want a redundant “tagged” section; you might want it to appear only on tiddlers that don’t already exist.
In that case, you might prefer to use the ViewTemplateBody cascade to show a special ViewTemplate only for missing tiddlers that are also tags. If you’ve never done this before, there’s a good introduction by @pmario here on Talk TW, and @Springer (who I believe pioneered this technique, and certainly coined the term “virtual node” to refer to missing tiddlers that still display useful content) has a demo wiki plus a number of posts on the topic, which ought to come up if you search for “missing tiddler”, “virtual tiddler”, or “virtual node”.