Seems everyone here is talking about "games in the Zelda sub-genre." I'd like to mention an actual Zelda clone (as it's a game I played for years, long ago—I don't know enough to endorse it in its present state): Graal Online.
Graal Online (or just Graal for short) is/was an MMORPG resembling Zelda: A Link To The Past in almost every way. In fact, it was originally called "Zelda Online" until they were served notice by Nintendo (the resulting changes were profoundly minor.) The game went through phases of being first a Java applet, then a Windows executable, and—most recently, it appears—a Facebook and iOS app.
It's basically what you'd expect from a Zelda game: a sword with damage levels and a shield that can deflect projectiles, bombs and arrows, rupees in bushes, Metroidvania-style "dungeon key-item unlocks more overworld" gameplay, etc. On the other hand, it's actually very programmable: it comes with (or, at least, used to come with) a built-in game editor, which can be used to construct one's own 64x64-tile maps, and Actor-modeled "Graalscript" sprite objects. (For example, you can drop any arbitrary image onto the map, and then add hooks for "was obtained," "was selected in menu," and "was fired," and you'll now have a new carryable item.) This content can then be pushed to the server where (after moderation) any group of players can wander in and interact with it. In fact, "outdoor" maps may actually get stitched right into the main overworld. (This is still my gold-standard for the concept of "player housing" in an MMO.) I would compare the usage-experience as similar to a 2D, Zelda-motif'ed Second Life, or a sprite-based MOO.
After a while, Cyberjoueurs (the creators) came to the money-making strategy of allowing people to run the server software on their own (centralized) game servers, charging a fee but allowing people to make money off those "Player Worlds" in turn. This then introduced waves of heavy customization, where little of the original Zelda mechanics remain in many player-worlds (the UI may be overridden at a low level in Graalscript to draw your own GUI, perform your own sprite animations in reaction to arbitrary key-presses, etc.) Because of this, most of the communal world-building aspect was abandoned, which is a shame. It does still seem to play a lot like Zelda, though :)
Graal Online (or just Graal for short) is/was an MMORPG resembling Zelda: A Link To The Past in almost every way. In fact, it was originally called "Zelda Online" until they were served notice by Nintendo (the resulting changes were profoundly minor.) The game went through phases of being first a Java applet, then a Windows executable, and—most recently, it appears—a Facebook and iOS app.
It's basically what you'd expect from a Zelda game: a sword with damage levels and a shield that can deflect projectiles, bombs and arrows, rupees in bushes, Metroidvania-style "dungeon key-item unlocks more overworld" gameplay, etc. On the other hand, it's actually very programmable: it comes with (or, at least, used to come with) a built-in game editor, which can be used to construct one's own 64x64-tile maps, and Actor-modeled "Graalscript" sprite objects. (For example, you can drop any arbitrary image onto the map, and then add hooks for "was obtained," "was selected in menu," and "was fired," and you'll now have a new carryable item.) This content can then be pushed to the server where (after moderation) any group of players can wander in and interact with it. In fact, "outdoor" maps may actually get stitched right into the main overworld. (This is still my gold-standard for the concept of "player housing" in an MMO.) I would compare the usage-experience as similar to a 2D, Zelda-motif'ed Second Life, or a sprite-based MOO.
After a while, Cyberjoueurs (the creators) came to the money-making strategy of allowing people to run the server software on their own (centralized) game servers, charging a fee but allowing people to make money off those "Player Worlds" in turn. This then introduced waves of heavy customization, where little of the original Zelda mechanics remain in many player-worlds (the UI may be overridden at a low level in Graalscript to draw your own GUI, perform your own sprite animations in reaction to arbitrary key-presses, etc.) Because of this, most of the communal world-building aspect was abandoned, which is a shame. It does still seem to play a lot like Zelda, though :)