craigslist - craigslist provides local classifieds and forums for jobs, housing, for sale, services, local community, and events
Wikipedia - Wikipedia is a free online encyclopedia, created and edited by volunteers around the world and hosted by the Wikimedia Foundation.
Yclas - The Most Suitable Classifieds Website Platform No advanced knowledge needed to have a classifieds website ready to start immediately Simple way to start a
Miraheze - Miraheze is a wiki farm (hosts wikis) for free and with no ads, it also provides custom domains...
OsClass - Open-source PHP classifieds script to create classifieds website within 3 minutes.
Oppia - Oppia is a free, open-source learning platform.