I came across this link recently:
It has a set of icons from a number of different operating systems, and from different versions of those operating systems going back years.
Many of these symbols will not apply in an embedded system, but others are more global – like ‘help’.
It is a handy place to browse if you think that your embedded system is going to borrow some symbols from the desktop world. In many cases the embedded application will have less resolution available than a modern PC, and so it might be worth looking at older, simpler versions of that icon.