Bucket and spade
Sandbox, or open world, games have been around in the tabletop games industry for a very long time. After all, that is exactly what role play games are all about. Every player pits their imagination and wits against the games master's plans. Nothing is impossible, within the rules of the environment of course, and every decision has consequences. However, when it comes to creating a convincing sandbox environment without using a games master you quickly reach limitations. Yet, there are a number of recent releases that create the illusion of a completely open world really well and in an elegant fashion.