HOIC (AKA: H.O.I.C., short for High Orbit Ion Cannon) is a free and open-source network stress testing and DoS/DDoS attacking application for Windows, Mac and Linux. It was written in Visual Basic and C#, developed by Anonymous (a hacktivist collective) during the Operation Payback after federal agents shut down Megaupload, and released as LOIC's predecessor.

Wolfram Mathematica is one of the most powerful and popular general computing systems in the world, as well as one of the most widely used mathematical software programs. Wolfram Mathematica, together with MATLAB and Maple, are called the top three mathematical applications. Since its first release in 1988, it has had a profound impact on how computers are used in technology and many other areas, performing well in almost every computing field, including network, graphics, geometry, data science, data visualization, machine learning, etc.

gEDA is a free, open-source and cross-platform (but mainly designed for Linux) EDA project. It provides a mature electronic design solution, including schematic diagram capture, property management, BOM (Bill of Materials) generation, 20 grid tables, analog and digital simulation, and printed circuit board layout (PCB suite, free software application).

bliss (full name elsten software bliss) is an intelligent, rules-driven, unique local music visual management software, developed with Java by Dan Gravell from United Kingdom. Unlike its peers, it runs on the basis of web browser and web data fetching. That is, the entire program only runs in the web browser rather than through an executable file, and requires an Internet connection.

diagrams.net (formerly called Draw.io) is a completely free, open-source, cross-platform and stand-alone flowchart drawing application that can be used as a browser-based web application, desktop application and plug-in for some other software. That's to say, you can use its web edition directly in a web browser (no registration required, no limitations, no catches), or use its desktop edition offline under Windows, Mac or Linux OS.