Confidential CC - Send self-destructing email without leaving a trace
DataMask.tech - Mask private data before taking screenshots
sup3rS3cretMes5age - A safe, simple tool for one-time (self-destructing) messages
Image Blur - Hide your sensitive data with a click
ShadowCrypt - Encrypts e-mails, Facebook status updates, tweets (Chrome)
GitGuardian - Detect secrets in source code, public and private!