Font Awesome is an icon based font created by Dave Gandy and the folks over at Fontawesome.io.
I wanted to bring this feature into Gamemaker as a way to create better graphics, icons, and buttons in people's games. I picked Fontawesome because:
1.) There are 675 icons to pick from (As of 4.7.0)
2.) The font is free to download (But we would recommend donating to the FontAwesome team at: https://gratipay.com/~davegandy/)
3.) The font "is fully open source and is GPL friendly. You can use it for commercial projects, open source projects, or really just about whatever you want.", according to their website.
Please be sure to read the Usage script after importing it to your project.