(I am aware that there are many paid methods that are faster and easier, this is only for free methods)
Emailnator and Yopmail
I found this when searching for Discord account generators on GitHub and reading the source code.
Disposable Gmail | Temp Mail
The emails sometimes work for me, other times nothing arrives.
You can also try Yopmail, a temp email service that I find less likely to be blacklisted on sites:
https://yopmail.com
Create a large amount of Proton accounts
Proton (
Proton Mail) is a well-known email encrypted email service. Unfortunately, when you try to create accounts, especially over Tor or when you already have an account, you'll be asked for email and/or phone verification. You can use Yopmail or Emailnator to get around email verification and Sms24.me (see below) to get around phone verification.
Sms24.me
Receive SMS online | Temporary Phone Numbers | Receive SMS online has a large amount of non-VoIP numbers, but they do not all work, and a few are VoIP numbers. Avoid the US and Canada numbers, these are usually VoIP numbers. Usually, to find working numbers, I click on a random number and find a message from Google or Discord and click onto the link with the sender's name, go to page 2-4, and find one of the numbers where the message was sent recently, and try using that number.
If you're using this to verify on Discord, I've tested it before, it sometimes works (even if the number has already had uses on Discord), but it is very hit-or-miss, you may get an error.
I do not know if this works on Google because I don't have a Google account.
Other email method (well known)
Add + (something) to the email, for example,
user@example.com becomes
user+blahblahblah@example.com. Delivers to the same email. Some sites don't consider it to be the same user. I did this to make a Discord account but I did reach phone verification (though this was likely because I was using Tor).