The open-source observability database. One columnar engine for metrics, logs, and traces, on object storage. - GreptimeTeam/greptimedb

A prior-art search for your code ideas — has this dev tool already been shipped? - r14dd/patent

A high-performance Ractor web server for Ruby 4.0+: Rack 3-based, with a Rust Tokio/Hyper front-end and Ractor-parallel Ruby workers and threaded fallback mode. - yaroslav/kino

Federated Nexus is a community resource hosting multiple FOSS (especially federated) services, including Matrix and Forgejo.

NoSignups (formerly FckSignups) is an open-source directory of no-signup, in-browser, open-source tools.