This thread made me think about my contacts as well. They are all stored with Google, which I access via the contacts app on my mobile phone. I can access my contacts via any of my other devices but, at the moment, with two factor authentication set up on Google, if I try to access my Google account, I will have a code sent to my phone! (Really useful if I have lost access to my phone.) Google provide 10 single use emergency codes which can be stored in advance, they can be used if you don't have your phone. I will put these in my password manager notes.
I don't know what other email providers allow though, it might be worth searching on the internet for information about emergency access to your email provider's website.
I know my landline and my mobile number and, this morning, I made sure I knew DH's mobile too.