I actually spent a bit last week looking for online CAH and was a bit overwhelmed - I somehow never knew that Cards Against Humanity was released under a Creative Commons license. Makes me want to buy all of the expansions even more, somehow.

EDIT: Just discovered that the CAH site linked by OP doesn’t work well on mobile, but found one that does: https://www.cardsagainsthumanity.online/

Here's another one. http://playingcards.io/game/remote-insensitivity

This site is also a good platform for card games in general