Garry's Mod!

This game is an open sandbox in which you may place items into the world and interact with them. Create your own levels and games while having fun and being creative.

ROBLOX is an online virtual playground and workshop - where kids of all ages can safely interact, create, have fun, and learn.

Algodoo, previously Phun, is an educational, entertaining and somewhat addictive piece of software for playing around in a 2D physics sandbox in a cartoon-y fashion. Algodoo is not just another game, but is intended to bring in interactive physics as an enabling technology for entirely new concepts and usage patterns in creative computing for animation, simulation, narrative-y, engineering, art and education.

Mythruna is a game under construction combining extensive world building, crafting, and sandbox elements with just a touch of role-playing. When completed, Mythruna will be a unique gaming experience.

An 8bit-style 2D massively multiplayer game! It's a giant construction sandbox -- you can build a home or a castle in a persistent streaming world. Found and manage your own city. Fight evil Lawyercats and engage in player vs player battle.

Tibers Box is a physical and a sandbox construction, based on the manipulation of various objects. Manipulation of objects can hold a great variety: from stretch an object and applying it to different types of textures to create a flying machine. Also in the game has a transport and npc that you can manipulate.Fans of the game garry's mod should enjoy it..

A game where you are on the moon and you must survive. There is crafting and many other strange things in this game.

Deepworld is a massively-multiplayer 2D crafting adventure game. Mine and craft your way through a persistent online universe where there's always something new to discover! Now available for Windows, iOS, and Mac, and coming soon to Android.

Golems Universal Constructor or Golems is a 3D recreational physics simulator.

16+Blip & Blop: Balls of Steel. What do the Smurfs, Super Mario Bros, Lara Croft and the Care Bears all have in common? They're all baddies in Blip & Blop! Although it is hard to believe, apparently these cute little friends are all actually pretty bad guys - and it's up to you to take care of them! Don't tell Papa Smurf you played this! (c) Loaded Studio. From 2002. For Microsoft Windows.

World of Padman is a incredibly meticulously designed and multicolored freeware fun-shooter for young and young-feeling people. You make your way through lilliput maps equiped with plastic guns.With 5 game types, 11 player models (even with diverent skins) and over 20 maps in different variations, WoP 1.5 is appareled with a ton of features and thus one of the biggest freeware shooters.

Block N Load is a 5 vs. 5 team-based FPS shooter similar in style to a combination of Minecraft and Team Fortress 2.

Blockade Runner is the beginning of a Multiplayer First Person Adventure Space Sim that will feature fully destructible, operational, crewable 'living' starships in a procedurally generated galaxy.

Across any terrain, with any weapon, against any opponent—the war must go on! Test your prowess with modern first-person shooter action in intense warzones ranging from labyrinthine urban locales to dusty desert battlefields. The gear, combat, and settings are designed to create an exceedingly realistic and fast-paced style of gameplay.