A word about icon fonts ...
Even though the plugin includes 16 different icon fonts, potentially giving you access to over 4,600 different icons, it is not advised to actually use all of them. Each icon font requires a CSS file, defining the class names and general styles for each icon, and the icon font file itself, which tells the browser how to “draw” the icon. Less active icon fonts means that less of those files have to be loaded.
Also, the more icons are utilized (not necessarily tied to the number of active icon fonts, as each icon font includes a different number of icons), the longer it will take Visual Composer to load and build the element settings panels that include a visual icon selector. It will take more time to build a visual preview of 2,500+ icons, than it does for 400 icons. So only activate the icons (icon fonts), you are actually planning to use.
If you do require a large number of icons, you should deactivate the visual icon selector in the plugin settings (tab “General Settings” -> section “Basic Settings”). That way, Visual Composer doesn’t have to build the icon previews anymore, substantially improving the time it takes Visual Composer to load and open element settings associated with icons. Instead of the visual selector, you simply manually enter the icon class name.