Cutie marks from official characters
Cutie marks traced from various sources by fans. Some cutie marks have official equivalencies, obtained through decompilation of various FiM flash games.
Cutie marks from fan characters/characters of indeterminate origin
Starburst cutie mark (quite similar to Twilight Sparkle's)
Squiggly arrows cutie mark
Snowflake with rainbow wings cutie mark
Green triangle cutie mark