Working As Intended's sandbox game Dawntide is focused on the creation of societies, cities, and an entire world based solely on player input, the sort of thing that's quite attractive to a number of players. The game has been in closed beta testing for quite some time, but if the premise intrigues you, there's good news on the horizon -- on May 31st, the game is going into fully open beta testing.
As the game approaches the deadline (which is very close indeed at this point), the development team is rolling out several improvements to the game. Those include a revamped and improved UI, a number of skills being implemented, and a stretch of islands available for players to claim as their own and build up as they see fit. If truly open-world gameplay appeals to you, the upcoming holiday weekend might be best capped off with a look at Dawntide's beta.
[Thanks to Bartillo for the tip!]