Cloudfogger - Easy and secure encryption for the cloud. Provides security for all cloud storage services like Dropbox, OneDrive and Google Drive.
Evernote - Bring your life's work together in one digital workspace. Evernote is the place to collect inspirational ideas, write meaningful words, and move your important projects forward.
BoxCryptor - Boxcryptor encrypts your sensitive files before uploading them to cloud storage services like Dropbox, Google Drive, Microsoft OneDrive, Box, and many others.
Standard Notes - A safe place for your notes, thoughts, and life's work
Mega - Secure File Storage and collaboration
Joplin - Joplin is a free, open source note taking and to-do application, which can handle a large number of notes organised into notebooks. The notes are searchable, tagged and modified either from the applications directly or from your own text editor.