The possiblity to add something (like a string or link) to the users clipboard as a button action would be a nice alternative to the openlink action. This would mimic the functionality of a vanilla gui where you are able to choose between directly opening a link in a browser or getting the link send to your clipboard instead.
(I actually don't know if this is already possilbe in current FancyMenu versions (mine's is 2.3.3-1.16.5) so basically I'm asking if there is a way to do it)
Vanilla example is from the Accessiblity Menu from Vanilla

Cool idea, will try to add this in one of the next content updates!

Added in FancyMenu v2.4.0! Thank you for your suggestion!