Octave

Octave is a scientific programming language with powerful mathematics-oriented syntax and built-in 2D/3D plotting and visualization tools

Tool	Category(s)	Developer(s)	License(s)
HELICS	Co-Simulation Frameworks	NREL , Pacific Northwest National Lab , Lawrence Livermore National Laboratory	BSD 3-Clause License
MATPOWER	Power Flow , Production Cost Modeling	Cornell University	BSD 3-Clause License