Lista de Freeware engines

Unreal Development Kit — UDK is free for noncommercial and educational use. Licensing terms are available to those who wish to sell UDK-powered games or to create commercial products for business use at www.udk.com/licensing.

Adventure Game Studio — Mainly used to develop third-person pre-rendered adventure games, this engine is one of the most popular for developing amateur adventure games.

Cocos2d— A 2d game engine for making iphone games.

DikuMUD and derivatives — MUD engines

dim3 — Freeware 3D javascript engine for the Mac (although finished games are cross platform).
Game Maker Lite — Object-oriented game development software with a scripting language as well as a drag-and-drop interface.

LPMud and derivatives (including MudOS and FluffOS) — MUD engines

MUSH — MU* engine

M.U.G.E.N — A 2D fighting game engine.

Open Scene Graph — An open source 3D graphics toolkit, used by application developers in fields such as visual simulation, computer games, virtual reality, scientific visualization and modelling.

Panda3D — (Releases prior to May 28, 2008) A relatively easy to use C++ game engine with Python bindings that was made by Disney and is owned by Carnegie Mellon University. Disney uses it to produce some of their games.

Platinum Arts Sandbox Free 3D Game Maker — Open source and based on the Cube_2:_Sauerbraten engine with a focus on game creation and designed for kids and adults. The program includes Non commercial content, but the main engine and large majority of the media can be used commercially. The Exciting Adventures of Master Chef Ogro was created using this engine by High School students.

TinyMUCK — MU* engine

TinyMUD — MU* engine

Unity — An open-ended 3D game/interactive software engine for web, Windows, and Mac OS X. Upgrading to paid licenses can additionally enable support for the iPhone, Android and Nintendo Wii.

World Builder — A classic Mac OS game engine.

Wintermute Engine — A runtime and development tools for creating 2D and 2.5D point'n'click adventure games.

RGSS — An engine made by enterbrain to create RPG's using RPG Maker XP. RGSS2 was used for RPG Maker VX.