Elude is an email service dedicated to protecting anonymity. You’ll need to download Tor to get to the site. Once you sign up, you can send e-mail to any e-mail client. When we tried sending a test e-mail to a Gmail account, it was sent to the spam folder. Granted, the site was just publicly announced under 2 months ago. Nevertheless, the site takes all sorts of steps to ensure anonymity and the site is completely free and easy to sign up for and has no identity validation required. You can use your account immediately after signing up.
This site is useful for journalists who are protecting their anonymity. Then again, if you want an anonymous e-mail account that will make it through Gmail spam filters, you might have to keep looking. A better alternative may be ProtonMail which also has both a regular and .onion portal along with apps. Then again, a popular service like ProtonMail might already have a backdoor in it.
You can find Elude’s .onion address on their website.