Mostly, we see success in the indie 2D world:
Don't starve - http://www.youtube.com/watch?v=MsWm_gWyk4s
Binding of Isaac - http://www.youtube.com/watch?v=c5PLC6nmOO4
Terraria - http://www.youtube.com/watch?v=GHPX0kR9h7I
And just released Starbound - http://www.youtube.com/watch?v=ZvrmB4tw33Q
Certainly 3D games are quite exciting in this space, too, but the 2D games seem to have a lot more traction with the big exception of minecraft.
I suspect it's simply easier to make an engaging sandbox when you don't have to worry about complexities in art assets that a 3D game requires.
Pro-tip: You need rocks, and you need them fast. Get all you can in the south, and then move northeast for the large rock pile. From there, you need to figure out how to survive the stronger enemies.
2) https://www.inovaestudios.com/ https://www.youtube.com/watch?v=a6a69dMLb_k (has been in development for years, about to start a campaign on kickstarter)
3) http://pioneerspacesim.net/ (free, open source, alreaady playable, alpha stage and actively developed)