Box - Box offers secure content management and collaboration for individuals, teams and businesses, enabling secure file sharing and access to your files online.
Uppy - The next open source file uploader for web browsers
Filecamp - Digital Asset Management & Online Proofing tools beautifully integrated, into one secure and cost-effective solution. Manage all your digital marketing assets from your own good-looking, easy-to-use spot in the cloud. Unlimited users in all plans!
Filestack - Simple file uploader and robust APIs for uploading, transforming, and delivering any file into your app. Filestack is a collection of tools and powerful APIs that make it simple to upload, transform, and deliver content.
Nubo - A self-hosted file sharing application in Haskell.
Uppy.io - Next open source file uploader for web browsers