https://github.com/gpepe/esp8266-sendemail
It took me a little while to figure out how to send emails using gmail thus here the template that worked for me:
SendEmail emailAccount("smtp.gmail.com", 465, "yourname@gmail.com", "password", 5000, true);
boolean emailSend = emailAccount.send("<yourname@gmail.com>", "<receipient@server.dom>", "subject","message");
Without the "<>" it won't work. Maybe somebody can explain? The examples provided with the library do not have them.