APEX Utils - Change Spinner
This small Dynamic Action plug-in enables you to replace the default APEX spinner with a custom one.
All you have to do is provide the HTML and CSS of your custom spinner. There are many resources online for free, awesome looking spinners. You can find a list on this plug-in's GitHub page.
Run this plug-in on page load, and every spinner from then on will be shown with the new markup. To replace all spinners application-wide, run this plug-in on the Global Page.