Miraheze - Miraheze is a wiki farm (hosts wikis) for free and with no ads, it also provides custom domains...
Investopedia - Investopedia has a lot of information to share with business mind people.
Fandom - The entertainment site where fans come first.
Fact Monster - FactMonster is one of the largest sources of information on the internet.
Wikiful - Wikiful is an online platform that makes it easy to build and share a wiki.
Editthis - A free wikifarm project allowing to keep private wiki and build it up through MediaWiki syntax.