Update July 2021: the style hub is now part of the official QGIS infrastructure at https://plugins.qgis.org/styles/
The 2016 post More icons & symbols for QGIS still regularly makes it to the top 10 list of posts by visitors. I wouldn’t attribute this popularity to the quality of this particular post, however. Instead, it’s a pretty clear sign that QGIS users are actively searching for more styling resources to add to their installations.
When it comes to styling resources, the person to follow right now is clearly Klas Karlsson who’s been keeping a steady stream of styling-related posts coming to Twitter:
Additionally, he’s the master-mind behind QGIS Hub, a – currently prototypical – platform for sharing styling resources and print layout templates:
If you are interested in sharing styling resources, head over there. Similarly, if you want to lend a hand developing QGIS Hub, get in touch!