[R5N3T]

Previously, there were Python-based tools for checking Gmail, Yahoo, and other email accounts. Are there any new ones available now?

[DramaKing]

Presumably, they became past tense when Google disabled SMTP auth. You would need to do this through HTTP now, discard all accounts with 2FA/2SV, and somehow get around CAPTCHA.

[Terry A. Davis]

somehow get around CAPTCHA.

India. Pay for CAPTCHA solvers, though I think the rates might be higher than what OP wants to pay for, I know that Google flags the account not the device as I've done some crafting on my personal accounts to know that it pings me across devices if I incorrectly enter my password a few times.

Much like Hotmail does the same that it will lock the account so if you go to sign in, it forces you to reset your password.