AUV Workbench - Freeware, simulation software designed for expensive AUV platforms, but easy to use with nice graphics. Developed by NPS Center for AUV Research, Naval Postgraduate School.

Player Stage - Freeware, robot simulation software, but not user friendly.

Microsoft Robotics Studio Visual Simulation Environment - Less than user friendly robot simulation software bought from AEGIS.

PHUN - 2D Physics Sandbox - Freeware, a 2D physics simulator that is *very* simple to learn and can even simulate water.

3D Graphic Robot Simulation - Graphic java-based 3D robot arm simulator

DMOZ Open Directory list - list of robot simulators

Sinbad - Java 3d robot simulator for scientific and educatioal purposes. It is mainly dedicated to researchers/programmers who want a simple basis for studying Situated Artificial Intelligence, Machine Learning, and more generally AI algorithms, in the context of Autonomous Robotics and Autonomous Agents.

Webots - very expensive professional robot simulation software

http://www.osrfoundation.org/

Open source simulators

• ARS: physically-accurate robotics simulator written in Python.
• breve 3d simulator using Python
• EZPhysics: Combination of Ogre3D and ODE physics, GUI exposes all of ODE's objects data, network closed loop remote control optionally via Matlab/Simulink.
• Gazebo: Probably the most complete open source simulator to this writing. Unless the deb precompiled package is used, it is notoriously difficult to install. It started as part of the Player project but is also used in ROS.
• Khepera Simulator Apparently before Webots became commercial it was open source and called Khepera Simulator
• Klamp't: a simulator introduced in 2013 specializing in stable trimesh-trimesh contact. Supports legged locomotion and manipulation.
• LpzRobots: Another rich simulator with good material support.
• Moby is a robust robotic dynamics simulator
• MORSE project provides a simulation tools based on the Blender 3D modeling software.
• OpenHRP3: (Open Architecture Human-centered Robotics Platform version 3) is an integrated software platform for robot simulations and software developments.
• OpenSim Simulator for articulated and wheeled robots with a wide range of characteristics. Further development stopped in the year 2006.
• ORCA-Sim: a simulator for robotics: is a (Windows) 3D robot simulator which incorporates the Newton Game Dynamics physics engine. A good alternative for Win32 platforms and the Gazebo project, with fast response and good performance. (Currently not open source. Last update in 2007)
• Robotics Toolbox for MATLAB is Free Software that provides functionality for representing pose (homogeneous transformations, Euler and RPY angles, quaternions), arm robots (forward/inverse kinematics, dynamics, simulation, animation) and mobile robots (control, localisation, plaing and animation).
• Simbad 3d Robot Simulator Java based simulator
• SimRobot: A robot simulator software package developed at the Universität Bremen and the German Research Center for Artificial Intelligence.
• Stage: 2.5D simulator often used with Player to form the Player/Stage system. Part of the Player Project
• UCHILSIM: A physics based simulator for AIBO Robots introduced in RoboCup 2004.
• v-rep (Virtual Robot Experimentation Platform): "the Swiss army knife among robot simulators". Note: v-rep has an open-source license (GNU GPL) but v-rep pro as well as some plugins do not.

Commercial simulators

• Actin Simulation toolkit for Robotics
• anyKode Marilou
• Cogmation robotSim
• COSIMIR
• Microsoft Robotics Developer Studio: As of 2008 R3, Robotics Developer Studio is a free download.
• RoboLogix
• SimplyCube
• V-REP PRO: 2 physics engines, kinematic solver, path plaing, 6 programming approaches, 6 languages.
• Visual Components
• Webots A generic simulator that can be programmed in C/C++, Java, Python, URBI and MATLAB
• WorkCellSimulator WorkCellSimulator
• Workspace 5 Robot and Automation Simulation

Research simulators

• UWA Robot Simulators