One-Time Secret - One-Time Secret is a way to share sensitive information simple and secure.
nohistory.fyi - nohistory.fyi is free to use webservice to share secret messages in a secure way.
Privnote - Send notes that will self-destruct after being read
1ty.me - If you need to send a password or some other form of simple but sensitive information to someone...
Password Pusher - Go Ahead. Email Another Password.
Revealit.me - ReveaiIt.me allows you to send a one time link to a self-destructing document.