Disclaimer: this is not an official documentation from Tor. This is an independent list of resources run by Tor users to help each other to understand and deal with a problem that they have to deal with on a daily basis.
For official documentation from the Tor Project, visit https://www.torproject.org/

Need some documentation about CloudFlare? Here it is!

• To get started: if you don't understand the CloudFlare problem or want to know more about it you can have a look at the Tor Project's fact sheet here.
  https://people.torproject.org/~lunar/20160331-CloudFlare_Fact_Sheet.pdf

• You can find a list of websites with CloudFlare blocks here. Some of them are always blocked, some of them block some exit nodes only. Feel free to add websites to the list.
  https://pad.systemli.org/p/cloudflare-tor
  or
  http://j7652k4sod2azfu6.onion/p/cloudflare-tor

• People have been discussing various issues around blocking Tor here - part of the conversations are about CloudFlare.
  https://pad.systemli.org/p/torblocks-philosophy
  or
  http://j7652k4sod2azfu6.onion/p/torblocks-philosophy

• Here's what CloudFlare says about the problem:
  https://blog.cloudflare.com/the-trouble-with-tor/

  Tor Responds to 94% Claim: "The Trouble with CloudFlare"
  https://blog.torproject.org/blog/trouble-cloudflare

• Here's how to remove the CloudFlare captchas on Tor on your website:
  https://support.cloudflare.com/hc/en-us/articles/203306930-Does-CloudFlare-block-Tor-

Most importantly: What can I do as a Tor user?

• You can reach out to CloudFlare to tell them what you experience when you use Tor. Talk to them on social media, send emails.
  Show them that you care. Explain why you want the situation to evolve.
  Stay polite. There's people like you and me working there, some of them are willing to help, no need to insult anyone.

• You can reach out to CloudFlare customers to ask them to whitelist Tor. Or even better, to switch to a Content Delivery Provider that supports Tor users.
  Talk to them on social media, send emails, use forms on websites.
  Show them that you care. Explain why it would be good for both sides (website & Tor users) if they would whitelist Tor.
  Here again, stay polite. CloudFlare customers don't all know about Tor and the CloudFlare problem, they may need some time to understand what's going on. Here too you are talking to real people who may be willing to help, no need to insult anyone.

• If you want to discuss the problem with CloudFlare customers and/or want to help them to help Tor users, it's better to be well informed before engaging in a conversation.
  Take some time to read the Tor Project's fact sheet.
  https://people.torproject.org/~lunar/20160331-CloudFlare_Fact_Sheet.pdf

• If a CloudFlare customer doesn't know how to whitelist Tor, you can send them this link
  https://support.cloudflare.com/hc/en-us/articles/203306930

• We used to recommend Donncha's Tor Whitelister tool. Don't do this anymore. This was good as long as CloudFlare didn't provide its own tool.
  Always recommend CloudFlare's tool if you want a CloudFlare customer to whitelist Tor. This works better and is easier to use.

• If you have a story to tell about CloudFlare you can tell it to Alison Macrina who is collecting them for Tor.
  Email alison at libraryfreedomproject dot org

• Be creative! Make art, jokes, create memes. Make it fun!
  Here's a collection of pictures about CloudFlare
  https://github.com/shiromarieke/cloudflare_stuff

And also...

Of course, CloudFlare is not responsible for all blocks on Tor websites. Check out the list of websites that are blocked for other reasons and feel free to participate!
https://pad.systemli.org/p/noncloudflare-torblocks
or
http://j7652k4sod2azfu6.onion/p/noncloudflare-torblocks

Oh, and have a look at La Quadrature du Net's aweseome fake CloudFlare captcha!
https://www.laquadrature.net/imsicaptcha/

Questions?
Contact @shiromarieke or marie dot gutbub at systemli dot org

French translation: https://github.com/shiromarieke/cloudflare_stuff/blob/master/cloudflare_fr.pdf