What email providers are you using for your reddit accounts?

I used to just use gmail, but I want more one-time use email providers.

Hmm well gmail is usually the best, though I have been using outlook and protonmail without any issues. Avoid temp mails as reddit will flag your acc and avoid your own custom domain mails.
Best to use are only: gmail, outlook, protonmail, yandex and similar big ones.

Outlook is good for onetime creation and verifying reddit, with quality proxies you only need to pass captcha to create an email account. I didn't need to use any phone verification. Use it as soon as you create it before it gets phone locked.

Gmail and Outlook work perfectly.
Just don't use any temp mail.