Have you ever thought about the problematic of printing?
1. Self-printed vs. printed material (first one shall have lesser colors to save ink as it becomes to expensive otherwise)
2. different paper formats, letter vs DIN
3. different bleed sizes (well for some it might work with and general bleed size but not for all)
4. different colors, EMEA ICC profiled, US CMYK and APAC very funny there very often the printer wants to do it by them self
For stickers it even becomes more problematic as it depends on the printing method.
So what is the problem, to come with the special need, when you need it?
There is a reason, why such pool doesnt exist. Work vs. Effort, the work will be to much. Even you talk about generic things, they have to be adopted all the time and that for just they ¨might¨ be used.
When something needs a change then, that the Ambassadors come not in the latest moment and know clear all the things we need. Besides that, the centralized production EMEA has and APAC tries to install makes more sense.