Zeal - Zeal is an API Documentation Browser.
DBeaver - DBeaver - Universal Database Manager and SQL Client.
DevDocs - Open source API documentation browser with instant fuzzy search, offline mode, keyboard shortcuts, and more
DataGrip - Tool for SQL and databases
Snippely - Snippely is a basic text and code organizational tool.
DbVisualizer - DbVisualizer is the universal database tool for developers, DBAs and analysts.