Collaborative online LaTeX editor with real-time co-editing, templates and reference-manager sync, available as a hosted service and an AGPL self-hosted edition
Posit's open-source integrated development environment for R, with console, editor, plots, environment panes, Quarto/R Markdown authoring and Python via reticulate
Markup-based typesetting system with an Apache-2.0 compiler written in Rust and a collaborative web app, positioned as a faster, simpler alternative to LaTeX