Phitbone is an SMS texting service with a focus on anonymity. You pay using Zcoin, in exchange for which you get a phone number that can send and receive SMS messages. Only a username and password are required. No email. No captcha. And no phone number... of course.
Phitbone offers physical phone numbers. Physical phone numbers are handy (as opposed to virtual phone numbers) because they can receive verification codes, such as the verification codes one receives when creating an email account.
There is one specific piece of the anonymity puzzle that Phitbone targets: decoupling SMS from identity. No anonymity tool works in isolation. Rather, Phitbone is part of an anonymity ecosystem. You should use it alongside other anonymity tools, such as the Tor Browser or the Tails OS.