This community (Meta Stack Exchange) has a nice icon:
Stack Overflow also has a nice icon:
However, take a site like Board & Card games. Their icon is a default:
That is very bland, and the icon for most communities. Stack Exchange could crowd-source their icons, as in asking the community to make icons and then use them. For example, I could suggest this image:
But, of course, this would get upvoted/downvoted by the community (and probably won't be used.)
So, I think this is a valid way to get icons for a Stack Overflow community, and will probably be a bit of fun for a few months.