Long time ago, I wrote some articles about Gazelle, a torrent tracker that became very popular for private trackers. The development has been long dead and many alternatives have emerged. One of them is Unit3D. Built on PHP Laravel, it is actively developped, modern and have a growing community of developers supporting the project.
BOINC for Berkeley Open Infrastructure for Network Computing, is an opensource platform using volunteering resources to compute useful calculations with the spare CPU/GPU cycles of your computer/server, for scentific researches.
Rtorrent is without any doubt the most powerful torrent client a server can have. Yet many webUI exists (Rutorrent being the most popular) but I personally prefer, by far, Flood. It uses Node.js for backend and React for frontend.
When you want to check how fast/good is your internet connection, you usually do a speedtest. In some cases, you may even want to host such speedtest in your infrastructure (Local network, network of customers,...) or just to provide such service to your community.