Meta Search - Search your Desktop, Google Drive, Dropbox, Gmail, Evernote.
Haystack Search - Haystack helps you make the most of your time, by searching all your files and documents in the cloud in one place. It's been built for privacy from the ground up, so your data isn't stored on a server, just your computer.
Google Cloud Search - Search across all your company's content in G Suite.
MailJack+ - Send PDFs as postal mail
Vaultedge - Access all your documents in one place.
Paperkit - Create and download custom graph, lined, or dot grid paper