Sites like taguette.org

OpenRefine is a free, open source desktop tool for cleaning, transforming and extending messy data

Peer-reviewed tutorials teaching humanities scholars digital tools and techniques, published in English, Spanish, French and Portuguese editions

Calibre, a free open-source e-book management software for converting, organising and syncing e-books across devices

Gephi, an open-source software project for visualizing and analysing network data through graph layouts, metrics and community detection

Open-source software for streaming your own music library from a self-hosted server, with apps and downloads

A Buffer product page presenting Start Page, a link-in-bio tool for linking social media audiences to content and offers

Afrofeminas is a Spanish-language online magazine, founded in 2014, on Afro-descendant and Black women's feminism in Spain

A multilingual online tool for building custom workouts by choosing equipment, target muscles and exercises

An international community developing free and open-source software, including the Plasma desktop and KDE applications

Wiki.js, an open source wiki software project for writing and publishing documentation, with versions 2.0 and 3.0

Mockoon, a free open-source desktop app and CLI for designing and running mock APIs locally, plus the Mockoon Pro team service

A weekly science and critical-thinking podcast, The Skeptics Guide to the Universe, hosted by the SGU skeptics team

Komga, an open-source media server for digital comic and manga libraries, with documentation and blog posts by developer gotson

Peergos is an open-source encrypted cloud storage service and drive, with its own client and server software

A self-hosted, open-source bookmark archive tool called LinkAce, built and documented by its developer, for saving and organizing web links

LibrePCB, a free open-source electronic design automation suite for drawing schematics and designing printed circuit boards, with a blog and documentation

netboot.xyz is an open source iPXE bootloader project offering a network boot menu of operating system installers, live distros and rescue tools

Vikunja, an open-source self-hostable task manager with lists, Kanban and Gantt views, with documentation and a Pro tier

PIKIMOV, a free browser-based motion design and video editor alternative to After Effects and CapCut, with tutorials and demos

Open source DCC and DC model railroad control hardware and software by the DCC-EX volunteer team, with products and setup guides

Actual Budget, an open-source personal budgeting app with desktop, web and self-hosted server versions, documented on its own site

Vale, an open-source command-line prose linter that checks documents against team style guides, by Vale Labs

AI-powered, self-hostable photo and video management app PhotoPrism for browsing, tagging, searching and sharing media

Woodpecker CI, a continuous integration server forked from Drone 0.8, with an awesome-list of related tools and tutorials

Syncthing, an open-source continuous file synchronisation tool, with project donation and foundation information pages

A free open-source tool for extracting data tables from PDF files, with downloads and release notes for Tabula

Tasks.org: documentation and product pages for Tasks, a free open-source Android task management app with CalDAV sync

Leantime, an open source project management software for teams, with a mobile app in beta

Lenny Rachitsky's newsletter on product management, growth, and career advice for product leaders and founders

Invoke, a free open-source self-hosted engine for AI image generation, with releases and developer documentation

Joplin, an open source note-taking app with multimedia notes, web clipping and end-to-end encrypted sync, developed by Laurent

BUTT, a free multi-OS live audio streaming tool for Icecast, Shoutcast and WebRTC, by developer Daniel Nöthen

I cannot tell from these pages what the site covers beyond a contact page, so the answer is:

BorgBackup, an open-source deduplicating backup archiver with compression and authenticated encryption, with documentation, release series and support pages

A Python plotting library documentation site for Matplotlib, covering static, animated and interactive data visualizations

Rocket.Chat, an open source team chat and collaboration platform for secure, self-hosted government and enterprise communications

SciPy, an open source Python library of algorithms for scientific computing, covering optimization, integration, interpolation, statistics and differential equations

Scikit-learn, an open-source Python library of machine learning tools for predictive data analysis, with documentation, FAQ and installation guides