All images are in the public domain, except as described below.
The Mythematics "geometric wizard hat" logo was designed by the amazingly talented Robot Arms, who also did all of the original character art for the Arithmetiquities and Chronicles of the Everflame Collective.
The Dungeons & Dragons ampersand logo is copyright Wizards of the Coast.
A number of icons are from game-icons.net and used under a CC BY 3.0 license. In particular, Pencil Ruler is by the artist Delapouite, and Sword and Spade is by the artist Lorc.