For ease of maintenance, I would be inclined to store the templates in drafts, all of which have a common tag (e.g. “Template”).
Make the first line of each Draft the template name, and the rest of the draft the actual template.
You can then search for all Drafts with the relevant tag. Display the first lines in the prompt, and then use the template based on the choice from the prompt.
If you need a new template just create the new draft. No changes to the code because the search will automatically find it.
It’s the same process I used in my Group email action.
Dave