Communication & Collaboration Matrix.org - A decentralized messaging platform. Zulip - An open source group chat application. Nextcloud - A cloud storage and collaboration suite. ownCloud - A self-hosted file sync and share server. Mattermost - An open-source team collaboration hub. Freenode - Internet Relay Chat (IRC) network for open source projects. GitLab - Web-based Git repository manager with CI/CD pipeline features. GitPod - A code ide that spins up dev environments with one click. Social Media & Forums Mastodon - A decentralized social network based on the GNU social/G+/Twitter microblogging platform software. Friendica - An open-source distributed communication and social networking platform. Flarum - A forum software that focuses on simplicity, speed, elegance, and usability. Discourse - A modern, open, and versatile discussion platform. phpBB - A popular open-source forum package. Fluentd - A data collection tool for collecting events from various data sources to a variety of destinations. Logstash - An open-source data processing pipeline that can collect data from diverse sources and channel it into a unified format. Kibana - An open source data visualization and exploration tool built on top of Elasticsearch. Developer Tools Docker - A platform for developing, shipping, and running applications. Jenkins - An extensible continuous integration server. GitLab CI/CD - Continuous Integration/Continuous Deployment. Travis CI - A cloud-based continuous integration service for GitHub and Bitbucket projects. JIRA - Project management software that includes scrum, sprint planning, backlog prioritization, release tracking features. Redmine - A free project management web application. Tuleap - An integrated project management tool combining the best practices in IT project management with modern and open-source tools. Email & Calendaring Roundcube - A web-based mail client. Horde Groupware Web Application Framework - A groupware suite. Zimbra - An email, calendar, and collaboration system. Sogo - A combination of a webserver component for iCalendar, vCard, and SMTP access and client libraries for various IMAP and CalDAV clients. DuckDuckGo Privacy Browser - A privacy-oriented browser based on Firefox. Data Management Elasticsearch - A distributed, RESTful search and analytics engine. Kibana - For visualizing Elasticsearch data in real time. PostgreSQL - A powerful, open-source object-relational database system. MongoDB - An open-source document-oriented database. Redis - An in-memory key-value store used as a database, cache and message broker. Memcached - A general-purpose distributed memory caching system. Neo4j - A graph database that allows for flexible queries using Cypher query language. InfluxDB - An open-source time series database. Office & Productivity LibreOffice - An open-source office suite. OnlyOffice - A platform that combines online text editors, document and project management, file storage in a single solution. Apache OpenOffice - Another free and open-source office suite. Zimbra Collaboration Suite - An email and calendar server with an optional desktop client. Infrastructure & Monitoring Nagios - A monitoring system for systems, networks, and infrastructure. Zabbix - An enterprise-class open source distributed monitoring solution. Prometheus - A monitoring system and time series database. InfluxDB - For storing and analysing metrics. Kubernetes - An open-source container-orchestration system for automating computer containers. OpenVPN - A robust and highly configurable VPN solution. NGINX - A high performance web server and reverse proxy server. Traefik - A modern HTTP reverse proxy and load balancer. HAProxy - A reliable, efficient, and flexible load balancing solution. Multimedia & Entertainment Plex - A client-server media management and streaming platform. Emby - An extensible media server and player with rich metadata capabilities. Radarr - A companion application to Sonarr for downloading new episodes of TV shows. Sonarr - An index based, TV show downloader that uses NZB files. Jackett - An indexing engine that searches many different websites. Deluge - A lightweight and feature-rich BitTorrent client. Rutorrent - An easy-to-use bittorrent client with a lot of features. Lidarr - An automated music indexer that can automatically download your favourite albums. E-commerce Magento Open Source - A flexible e-commerce platform for businesses of all sizes. PrestaShop - An open-source e-commerce solution. OpenCart - A free, open-source shopping cart system. WooCommerce - A WordPress plugin that turns your site into a fully-fledged online store. Security fail2ban - A network security tool that analyses log files for failed login attempts and then bans the IP addresses of those who succeed in multiple unsuccessful login attempts. Cryptography - Tools and libraries for encryption and decryption. OSSEC - A powerful open-source host-based intrusion detection system. Pulse Secure Virtual Desktop - A secure access service edge (SASE) platform that enables organizations to deliver integrated, cloud-first application and network access security. ClamAV - An open-source antivirus engine for detecting Trojans, viruses, malware, and other malicious threats. Cloud & Storage OpenStack - A cloud operating system for delivering various cloud services. Cloudflare - An internet performance and security company that provides a network of distributed servers to protect websites from cyber attacks. Nextcloud - Already listed earlier, but worth mentioning again as it’s also a full-fledged cloud service. OpenVPN - For creating secure remote access to your home lab. Web Servers Apache HTTP Server - The world’s most widely used web server. NGINX - A high performance HTTP and reverse proxy server. Caddy - An automated web server with automatic HTTPS. Developer Tools & IDEs Visual Studio Code - A code editor redefined and optimised for building and debugging modern web and cloud applications. Eclipse - An open-source integrated development environment (IDE). IntelliJ IDEA - A powerful IDE for JVM-based languages like Java, Kotlin, Scala and Android. Learning & Educational Resources Khan Academy - Provides free online education for a variety of subjects. Moodle - An open-source course management system that can be used to create an online learning environment. Canvas - A cloud-based learning management system (LMS). edX - An online learning platform founded by Harvard University and the Massachusetts Institute of Technology. Game Servers Minecraft Server - To run your own Minecraft server. SteamCMD - Steam’s content delivery tool to help manage game updates on dedicated servers. ARK: Survival Evolved Server - To host a survival multiplayer game server for ARK. File Storage & Backup BorgBackup - A deduplicating backup program that supports file and block storage. Bacula - An open-source enterprise-level data protection, restore, and recovery system. Rclone - A tool to sync directories between cloud storage providers. Media Streaming & DVR Emby - For centralized media streaming within your network. MediaPortal - A free open source media centre software for Microsoft Windows. DVR-PC - A complete TV recording, streaming and live TV viewing solution that runs on Linux (and Windows) PCs. Other Tools Mattermost - Team communication tool, which also has a collaboration suite component. GitPod - A web-based code server with pre-configured tools for full-stack development environments. GitBucket - An easily installable GitHub compatible Git server written in Scala. Zabbix - For monitoring your infrastructure and applications.