Gmail is the best and I will tell you why.
When they ask for your phone number, do not put it in. There will be an option somewhere down stating "Try different method to reset password".
Choose it, they will ask you for old passwords. Try your luck there.
If you don't remember it then say so, there is a option for that too.
Use the device and the network which you used last time to do this process, they track IP addresses of previous sessions.
They will ask all sorts of details about your account like linked accounts, numbers, birthdate, etc.
In the end, as the other answer says, you can contact them via the same process (if the info you provide is not 100% correct, they will provide this option automatically).
This process involves further details which only the owner knows.
Good luck and if possible, share your experiance here for future visitors.