Salem vs Ylands
Salem
Salem is an old-school and somewhat obscure (but fun) sandbox MMORPG that unlike Wurm Online has a stronger emphasis on its in-depth crafting system and survival aspect rather than building.Similar to Wurm Online though, Salem is not a voxel-based game, but you are still able to mold the game environment through resource gathering, mining and digging in a way that reminds me of the currently-shelved MMORPG, EverQuest Next: Landmark. Of course, although not exactly the focus of the game, you can still build your homestead and the process is quite similar to Wurm Online except that it occurs at a much higher speed.
Not to mention, the game world in Salem is simply humongous to the point where it feels like an actual world. Salem also borrowed some features from ArcheAge where open-world PvP is the norm, so you'll need to be vigilant at all times, but players who kill and steal for no reason will be labelled as criminals and can be punished.
However, as good as it is despite being an indie MMO and all, Salem does have its fair share of flaws due to its low development budget. So, we'd recommend you to take a look at Salem without carrying along any high expectations. It's a pretty good MMORPG like Minecraft, but if you're expecting a Minecraft clone, you may end up disappointing yourself.
Ylands
Ylands is a sandbox adventure game that has a gameplay that's a lot like a massively expanded version of Minecraft with a lot more resources for you to gather, items to craft, and amazing things to build. Instead of being "just a game", Ylands is more like a platform, much like Roblox is, where players are given the tools to create whatever worlds or games they like, be it a fun go-kart racing game that's inspired from Lega Racers or even a watery world where epic pirate-themed naval battles can take place. The worlds are completely interactive as well and every action you do will modify, no matter how slightly, the game environment of that segment of the world you happen to be in. In fact, if you change a terrain and populate it with an entirely different diversity of flora and fauna, you can basically change the climate system there.Unlike Minecraft though, Ylands has opted for a more polygonal appearance which gave it the extra leverage it needed to overcome the painful dismissal and degratory label of being simply a "Minecraft clone" - which admittedly, Ylands is most definitely not. The game has so much going for it and players truly have all the freedom within the game's pretty wide parameters to literally create anything they like. Of course, the game also supports sharing, so you can let other players in Yland enjoy that (for example) crazy maze-running game you've just made!
Ylands is most certainly impressive to say the least. However, due to its indie origins, not many players know about the game, let alone buy it on Steam. So, if you really like Minecraft-like sandbox games, you simply must give this game a try, and if you've had a great time there, be sure to recommend it to your friends or even buy it for them as their Christmas/ birthday gift!