Google typography is a FREE plugin for WordPress that allows anyone (and mostly non-techies) to use any of the 600+ fonts from the Google Fonts database and apply them to any font on their WordPress site without writing a lick of code. This is a very nice plugin that I’ve not discovered any compatibility issues with it and other plugins I use.
G-Font does everything Google typography does plus more but it has some minor issues and is NOT free. G-Font and TinyMCE plugins were NOT initially compatible. As soon as I activated the G-Font plugin, all Visual editing capability was lost, there were no menu items and no text/graphics displayed, not even the editing area appeared. Only Text editing was available. I pointed this out to its creator and he has improved it significantly. I experience a few glitches when both are active but generally they work together.
I use Ultimate TinyMCE for most visual editing and ALL icons vanish when G-Font is activated. If I deactivate Ultimate TinyMCE plugin, then the G-Font plugin seems to work and visual editing is back with about 5% of the icons I use with Ultimate TinyMCE. Here one can either choose which to keep and discard the other or consistently switch between them by disabling one before enabling the other.
Another issue with G-Font is that it will not work on a local host envionment with XAMPP, it results in a message stating, “Plugin could not be activated because it triggered a fatal error.” Its developer had me check some Xampp settings and nothing needed changing but it activated and worked. Not sure what caused the initial issue.
There is also a paid version called Ultimate TinyMCE Google Webfonts. I have not yet tested this. Google Webfonts is included in Ultimate Tinymce PRO for free.