Back with Magic: The Gathering was young, Wizards of the Coast produced its first of several artifact-based sets and introduced us to the Brothers War, a planet and eventually planar conflict between Mishra and Urza
As for the card itself, Miku's Spark takes the Sakura design and gives it a bit of a "Spark" as the name suggests, adding some pink lighting that Miku is casting
If you look at artifacts from the early days of Magic (like Alpha/Beta/Unlimited ), on noncreature artifacts, you'll see that there's extra words on the type line: "mono", "poly", and "continuous"
Magus of the Wheel Wheel effects are useful, whether you benefit yourself with the card draw, or punish opponents for drawing and/or discarding
Teval is leaps above the zombie partner commander with the power to mill and return lands from your graveyard on top of your regular one land per turn
More treasure cards would appear in Rivals of Ixalan , a small expansion set, released in January of 2018