All of the official expansions are provided by Catan.com and are officially sanctioned by Catan LLC. The fan expansions were created or translated by users at BoardGameGeek. The individual variants are listed here for public use. All rights reserved to authors.
Official Catan Game Variants
Major Fan Variants
Cooperative Play by Roee Anuar (DOC) - A cooperative-play version of Settlers
Kindercatan by Chris Gregg (PDF) - A 2-player variant for ages 4 and up
Preschoolers of Catan by Bill Yakowenko (TXT) - A variant for very young kids
Minor Fan Variants
Raze and Pillage by Richard Cox (DOC) - Unoccupied hexes now receive resources. Who will build there first and cash in?
Welfare by Douglas S (DOC) - Make sure that no player takes the lead right away
Catan Variants Pack by Jacob Busby (DOC) - A variety of minor variants to try
Escaping the Overpopulation by Itomi Bhaa (PDF)
Orient, Septentrion and Occident by Itomi Bhaa (PDF)