Show tags in tag group only being used on live entries
Your mention tags, but it seems like you're merging Categories and Tags together and trying to loop through the results.

If you leave Categories out of the equation it's as simple as this.

If you want Categories and Tags, you'd repeat that process twice and merge the results.

Note that using |merge on full-fledged arrays of objects is sketchy, though, since it's difficult for PHP to know how to compare the objects for equality.  You'll be much better off merging on something primitive, like an array of element IDs.

Something like:

{% set categoryIds = craft.categories.group('storiesCategories').ids() %}
{% set tagIds = craft.tags.group('storiesTagGroup').ids() %}
{% set elementIds = categoryIds|merge(tagIds) %}