I was compiling this list anyways. AFAIK the most recent extra/preview is the only one with a PDF file to download it.
Designers Notes
Dungeon Fantasy Designer’s Notes 1: What, Who, When, Where, Why?
Dungeon Fantasy Designer’s Notes 2: Eleven Flavors of Munchkin, a Golf Bag Full of Swords
Dungeon Fantasy Designer’s Notes 3: Fighting (and Other Activities)
Dungeon Fantasy Designer’s Notes 4: “It’s Magic!”
Dungeon Fantasy Designer’s Notes 5: Jaws That Bite, Claws That Catch
Characters
Lyndon Glibtongue, Elven Bard (Project Update #29)
Amira Tiro, Half-Ogre Martial Artist (Project Update #42, Kickstarter Backer Exclusive)
Emily Elms, Halfling Scout (Project Update #90;
PDF)
Glint, Human Martial Artist (promo PDF)
Spells
Land Mine (Game Geekery)
Retribution (Project Update #39)
Rebuke Evil (Project Update #89)
Monsters
Fae Reaver (Enworld)
Squirrel-Pion (Project Update #45)