An Old school D&D Sandbox Campaign ?

The Southern Reaches is a West Marches type using a Simplifed version of the OGL (D20) rules called MICROLITE20

The Campaign World

Go South Young Men!

The City of Ophal is the last bastion of civilisation before the dreaded Southern Reaches. Only the brave and the fearless venture south into this unexplored region of the world, for tales of great perils and greater riches are told by the few that come back from the Southern Lands.

Luckily for the brave adventurers within the city of Ophal they can find all the convinence needed to embark on their expeditions.

The Southern Reaches (Microlite20)