Open Source Software for Linux
FileZilla
Filezilla is an free and open-source FTP software that can be used to transfer files over the FTP, FTPS and SFTP protocol. The application consist of FileZilla Client and FileZilla Server. The FileZilla Client is used to connect to FTP services whereas FileZilla Server can be used to create and host your own FTP server.
Netcat
With Netcat you can read and write data across network connections with the TCP/IP protocol. Netcat is a feature rich networking utility for macOS, Linux and Windows that is designed to a reliable tool that can be utilized by external programs and scripts. Netcat provides intricate tools for netowork debugging, network exploration and connection creation.
Wireshark
Wireshark is the world's most widely-used network protocol analyzer software. With Wireshark you can get a better understanding on what's happening on your network. The software let's you do deep analysis across hundreds of protocols at a microscopic level. Wireshark is free and open-source and has been in active development by contributions from volunteers across the globe since 1998. Today the software is used by commercial and non-profit enterprises, government agencies, and educational institutions.
Akira UX
Akira UX is a free an open-source graphic design software built with Vala and GTK. The application offers a fast approach to UI and UX Design, mainly targeting web designers and graphic designers. Akira UX is available for all major Linux distributions, and through the elementary OS AppCenter.
Pencil2D
Pencil2D is a simple, yet powerful 2D animation, drawing and painting application that lets you create traditional hand-drawn animation using both bitmap and vector graphics. Pencil2D is released as free and open-source software under the GNU General Public License and uses the Qt framework. With Pencil2D you can seamlessly switch between raster and vector workflows, allowing you to sketch, ink & paint on the go.
Grafana
As the world's most popular free and open source technology for visualizing metrics, Graphana makes it easy to create a interactive dashboard for data monitoring. Grafana's designed from the ground-up for analyzing and visualizing metrics such as system CPU, memory, disk and I/O utilization. All metrics provided by connected data sources and applications can be visualized and monitored though charts, graphs, and alerts. You can also extend the core functionality of Graphana through a built-in plug-in system. Popular companies and applications like Uber, Robinhood, Nubank and others trust Graphana and its real-time visualization and monitoring capabilities.
Deno
A new free and open-source JavaScript runtime based on the V8 engine by the creator of Node.js, Ryan Dahl. Deno is written in JavaScript and Rust and allows you to write server-side application with JavaScript or TypeScript in a faster and more secure way. Ryan Dahl set out to create Deno from the ground up to remedy regrets he faced after building Node.js. Deno puts more focus on security and permission, promises, browser capability, imports and modules.
Packet Sender
Packet Sender is a free and open source utility to allow sending and receiving network packets, with support for TCP, UDP, and SSL. The tool is designed to be while still providing enough features for power users to do what they need, allowing anyone to manage packets according to their needs. Packet Sender is most commonly used for testing network APIs, malware analysis, testing network connectivity/firewalls and security research.
DDEV
DDEV is an open source tool that makes it dead simple to get local PHP development environments up and running within minutes. It's powerful and flexible as a result of its per-project environment configurations, which can be extended, version controlled, and shared. In short, DDEV aims to allow development teams to use Docker in their workflow without the complexities of bespoke configuration.
Double Commander
Double Commander is a cross-platform open source file manager with two panels side by side. The application takes inspiration from Total Commander and brings new features and ideas to file management. With Total Commander all archives are handled like sub directories and you can easily copy files to and from archives. Supported archive types include ZIP, TAR, GZ, BZ2, XZ, LZMA, 7Z, RPM, CPIO, DEB, RAR and ZIPX.