Miraheze - Miraheze is a wiki farm (hosts wikis) for free and with no ads, it also provides custom domains...
Pocket - When you find something you want to view later, put it in Pocket.
Fandom - The entertainment site where fans come first.
Raindrop.io - All your articles, photos, video & content from web & apps in one place.
Wikiful - Wikiful is an online platform that makes it easy to build and share a wiki.
Tettra - Tettra is a company wiki that helps teams manage and share organizational knowledge.