There are a couple of ways you could do this, but I think it’s easiest to use the conditional <% if %> syntax, which is simplest “modern” replacement for $reveal. For instance:
<% if [tag<currentTiddler>tag[Family]] %>
! Family
<$list filter="[tag<currentTiddler>tag[Family]]" />
<% endif %>
You’ll notice that this has us running the same filter twice: once in the conditional (to determine whether anything is displayed at all), and once to enlist the results, if they exist. Your wiki’s tags are automatically indexed for faster filtering, so this shouldn’t be a terribly resource-intensive task. But if you were using a more complicated filter, you might prefer not to run the whole thing twice!
Luckily, the conditional syntax has a special property: its first result is automatically assigned the variable <<condition>>. (This is because <% if %> is actually just a prettier wrapper for a specific $list — happy to expand more on that if you’re curious.) We can take advantage of this property by using +[format:titlelist[]join[ ]] to save all the results of the filter as a single, space-separated title list, which gets assigned to <<condition>>…
<% if [tag<currentTiddler>tag[Family]] +[format:titlelist[]join[ ]] %>
! Family
<$list filter="[enlist<condition>]" />
<% endif %>
… and then use [enlist<condition>] in the $list widget to return that title-list string to a list of separate titles. If the initial filter is complex, this can be significantly more performant.
Finally, if you want the same output for each category, and the target tag is the only thing that varies between lists, you might want to move this code into a procedure so you don’t have to paste it 3+ times. This should also make it easier to change the template/styling in the future, since you’ll only need to update the procedure definition. So here’s my final recommendation:
\procedure list-category(tag)
<% if [tag<currentTiddler>tag<tag>] +[format:titlelist[]join[ ]] %>
! <<tag>>
<$list filter="[enlist<condition>]" />
<% endif %>
\end
<<list-category Family>>
<<list-category Health>>
<<list-category Finances>>
<<list-category "This tag has spaces!">>
P.S. The above code assumes that your category tags are already capitalized. But perhaps they’re not… and perhaps you’d still like your headers capitalized. In that case, you can style them with the following CSS, either present in the tiddler where you intend to use the procedures or added (minus the <style></style> tags) to a stylesheet of your choice:
<style>
.capitalize { text-transform: capitalize; }
</style>
Then modify your header to include this new class (along with any other styling you prefer):
!.capitalize <<tag>>
The nice thing about this approach is that it doesn’t change the underlying value of <<tag>>, just the way it’s displayed. This means that if you wanted the header to link to the category tag, for instance, you could do so without issue:
!.capitalize <$link to=<<tag>> />
P.S the second: Just realized you said “transclude entries”, not “link to entries”. In that case, you could modify the $list template:
<$list filter="[enlist<condition>]">
<$link /> <!-- if you want a direct link to the tiddler as well -->
<$transclude $mode=block /> <!-- or add $field=field-name if you want to transclude a field other than the main text. Either way, I recommend using $mode=block to preserve linebreaks and other block formatting. -->
</$list>
