Parameters tags for grouping
It'd help if one could tag Parameters and have a dropdown to select the tag groups.
Say I tagged all my favourite smile expressions as "smiles" from a right-click submenu and name the tag, then have a drop-down under the filter list where I can select "all" or "<tag name>" to only display those.
Think Favourites on steroids, plus Favourites are scene specific, I'm speaking global for any DS instance.

Comments
I think it's a good idea. But actually you're able to make it by using a workaround, i.e. the latest Regular Expression filtering system in DS 4.22+, for instance, by using Color B. You can:
1) Specify a unique color in Color B slot of all your favorite smiles expressions / facs; ( batch modify them by turning on Edit mode... select properties, Set > Presentation > Color B ...)
2) Save Modified Assets. (File > Save As > Support Asset > Save Modified Assets...) Then filter it by Presentation > Color B. This solution is not Scene-based but a global settings based on Genesis figure.
In this way, you "tag" the properties by using different Color B as well as different values in RegExp accordingly. Save filters as, for instance, My Fav. Smile, My Fav. Anger., so on and so forth.
Edit: Be noted, in case if there's any product updates to the expression / facas properties that you ever modified, the modified value will be updated. In that case, you have to change them again...
Not bad. Gonna try that, thanks.