WeTransfer - WeTransfer is a free service to send big or small files from A to B.
ShareX - ShareX is a free and open source program that lets you capture or record any area of your screen...
Wormhole.app - Wormhole lets you share files with end-to-end encryption and a link that automatically expires.
Greenshot - Greenshot is a free and open source screenshot tool that allows annotation and highlighting using the built-in image editor.
Dropbox - Online Sync and File Sharing
LightShot - The fastest way to take a customizable screenshot.