I think a nice "overview" about the subject can be found at: Quantiki
They have a list of quantum computer simulators in several languages, some of the simulators hashave been cited here before. However, they keep thea list that they update andto inform (or try to inform) the status of the projectproject's status. There are some "libraries" such as:
Haskell
qchas (qchas: A library for implementing Quantum Algorithms) - A library useful for implementing Quantum Algorithms. It contains definitions of Quantum Gates, Qubits.
Python
qubiter : The Qubiter project aims to provide eventually a full suite of tools, written mostly in Python, for designing and simulating quantum circuits on classical computers.
Javascript
jsqis : jsqis, at its core, is a quantum computer simulator written in Javascript. It allows initialization of quantum registers and their manipulation by means of quantum gates.