The KM Trigger Macro by Name action (KM Wiki) does not have a provision for default search text, so you will need to consider alternatives/workarounds:
- Have you tried just typing "aff" ? That might be enough to filter the macro list sufficiently.
- I often add "text keywords" to my macro titles, like "@AFF". That should uniquely identify your macros of interest.
- You could use the custom macro by @DanThomas to search/execute macros, and customize it to fit your needs: