BURN.link - Send secure, encrypted, self-destructing messages
1ty.me - If you need to send a password or some other form of simple but sensitive information to someone...
Confidential CC - Send self-destructing email without leaving a trace
Boop - A scriptable scratchpad for developers. Free & open source!
Image Blur - Hide your sensitive data with a click
Burner Note - Burner Note is a free, ad-free and open sourced service for sending secure text based notes that are completely erased from existence once they've been read.