40 Alchemical Items
Adamant Entertainment: d20 3.5 (2005 PDF)

40 Years of Gen Con
Atlas Games: Generic 1 (2007 Hardcover)

43 AD
Zozer Games: 43 AD 1 (2012 PDF)
Zozer Games: 43 AD 1 (2013 )

43 Space Opera Adventure Seeds
Polgarus Games: Generic 1 (2007 PDF)

44: A Game of Automatic Fear
Self-published: 44 1 (2009 PDF)

4C Expanded
James F Keck: 4C Expanded 2 (2018 )
Keck Publishing: 4C Expanded 2 (2018 )

4C Expanded Monstrous Compendium
James F Keck: 4C System 1 (2022 )
Keck Publishing: 4C System 1 (2022 )
James F Keck: 4C Expanded 2 (2022 )
Keck Publishing: 4C Expanded 2 (2022 )

4C Super Agents
Seraphim Guard: 4C System 1 (2008 PDF)

4C Super Teams Super Bases
Seraphim Guard: 4C System 1 (2008 PDF)

4C System
Self-published: 4C System 1 (2007 )

4C System: Weapons & Gear
Self-published: 4C System 1 (2008 PDF)

4E Utility Pack
Made by Wombat: Dungeons & Dragons 4 (2009 Box)

4th Edition Races and Classes
Self-published: Dungeons & Dragons 4 (2008 PDF)