Thank you so much for this, Dan!
It's brilliant in many ways, but I think my favorite is this: it integrates seamlessly into my existing macro-construction workflow. I installed it, set the hotkey to mimic the "Insert Action -> By Name…" menu item, continued doing things mostly as before, and just like that began to build my library of favorites. The other nice touches -- customizing, sorting, renaming, etc. -- are so easy to learn and add incrementally as the need arises.
What I mean to say is: I'm able to keep using KM the way I was, only faster and better, and with almost no transitionary period of learning a new way to work.
I have only one suggestion for improvement. Sometimes (usually after creating a new macro), I will summon KMFAM while the macro title field is active (i.e., while the text cursor is blinking in the macro title field). In these cases, after I select an action, KMFAM silently fails without adding the action. I hope I've explained this well enough; please let me know if you need more details.