Free and Open Source Software
Epiphany
Surf the web with a fast & lightweight web browser. Epiphany is a web browser built specifically for elementaryOS that lets you use modern websites and web apps while being lighter on battery life.
Tails
The Amnesic Incognito Live System or Tails for short is a portable operating system that protects you against surveillance and censorship. The operating system can started from a USB stick on any macOS, Linux or Windows computer, leaving no trace on that computer after it has been shutdown. Allowing you to make any computer into a Tails protect environment free of surveillance. Tails includes a variety of open source tools that can be used to browse the web, edit document and communicate saftley. Including Tor, Tor Browser, Pidgin, Network Manger, VeraCrypt, GNUPG, MAT, KeePassXC, GtkHash and many more.
CapRover
CapRover is an free and easy-to-use application deployment and server manager for NodeJS, Python, PHP, ASP.NET, Ruby, MySQL, MongoDB, Postgres, WordPress and more. With CapRover you can create your own PaaS (Platform-as-a-Service) similar to that of Heroku, and deploying it to your own cloud instance.
MonetDB
MonetDB is an column-oriented database management system developed at the Centrum Wiskunde & Informatica. The database is released as free and open source software under the Mozilla Public License 2.0. By design, MonetDB can handle high performance on complex queries against large databases with hundreds of columns and millions of rows.
Sia
Sia is a decentralized storage platform secured by blockchain technology. The Sia Storage Platform leverages underutilized hard drive capacity around the world to create a decentralized data storage marketplace that is more reliable and lower cost than traditional cloud storage providers. With Sia you can store files in the decentralized cloud without signup requirements, servers and trusted third-party providers. On average, Sia's decentralized cloud storage costs 90% less than incumbent cloud storage providers. Storing 1TB of files on Sia costs about $1-2 per month, compared with $23 on Amazon S3.
Stacker
Check the top of the screen to. see what's next and its width. Some ladies wear fruit on their head. Who ate all the shapes? You stacked the lot!
Apache Geode
Apache Geode is a mature, robust distributed in-memory data grid supporting caching and data computation. The software originally developed by GemStone Systems. Commercially available as GemFire. With Apache Geode you can provide low latency, high concurrency data management applications.
Seafile
Seafile is an open source file sync & share solution designed for high reliability, performance and productivity. Sync, share and collaborate across devices and teams. Seafile can be self-hosted, or provided as a managed and hosted solution. With Seafile, you can rest assured that your files are safe as all files are encrypted before syncing with the server, even system administrators have the capability to view your personal files.
Qt
Qt includes everything you need to build cross-platform applications that run on various software and hardware platforms such as Linux, Windows, macOS, Android or embedded systems with little to no change in the underlying codebase. Qt is released open-source under the GNU Free Documentation License, and provides a commerical offering for enterprises.
Brackets
Brackets is a modern, open sourc ecode editor that is lightweight, yet powerful. The editor features a blend of visual tools and a clean user interface packed with features like Live Preview, Quic Edit and Preprocessor Support. With Brackets you can design and develop for the using technologies like HTML, CSS and JavaScript.