I just learned something recently on how to make custom icons for your MapsForDesign Map Presentations. Using the Wingdings and Zapf Dingbat fonts built right into your PC you can make all kinds of cool icons.
Watch this video from Presentation Process on how. I found the Mac PowerPoint options a little different, be very similar. They are in there.
How to Create Stunning Editable Icons in PowerPoint in 16 Seconds from Presentation Process