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.
Meta Search - Search your Desktop, Google Drive, Dropbox, Gmail, Evernote.
Standard Notes - A safe place for your notes, thoughts, and life's work
Vaultedge - Access all your documents in one place.
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.
Google Cloud Search - Search across all your company's content in G Suite.