@00taffe I don't know all the alternatives, I heard of Papeeria too !
Let's focus on sharelatex, they are the one who got me into latex, because the interface is user friendly and they have a very good SEO.
They also seem to have a neat integration with Dropbox and Github which I did not find elsewhere.
Finally https://fr.sharelatex.com/learn/ is a good documentation with practical use cases.
Pictionary for iMessage
DiffSense