Mapus is an open source tool to explore and annotate collaboratively on a map. You can draw, add markers, lines, areas, find places to go, observe other users, and much more.
Corona Data Scraper pulls COVID-19 Coronavirus case data from a variety of openly available world government data sources and curated datasets. It finds the corresponding GeoJSON features, and adds population data.
SmallWorld.js is a utility for generating map overviews using GeoJSON and HTML Canvas. It was created out of a need to render simple map previews, quickly and efficiently without heavy client libraries.