Redsmin - All-in-One GUI for Redis. Thightly crafted developer oriented, online real-time monitoring and administration service for Redis.
pganalyze - PostgreSQL performance monitoring installed within minutes
usql - Universal command-line interface for SQL databases
pgDash - pgDash is a comprehensive monitoring solution designed specifically for PostgreSQL deployments. pgDash shows you information and metrics about every aspect of your PostgreSQL database server, collected using the open-source tool pgmetrics.
Errbit - The open source error catcher that's Airbrake API compliant
PgHero - Rails database insights made easy. Add the gem, get a dashboard with long running queries, cache hit rate, and more.