Horizon Seeker I think re-useable land tutoring is good, snow-lands are basic lands, so that's neat, 3 to get out and 2 to use is a lot of mana to invest in a potential land tutor for a basic though, and it's not an elf, but rather a human warrior, which generally tend to be white (though obviously not always)
You would have to make sure your opponent is discarding to get this to work, and that's not that difficult
Aside from the aforementioned Act on Impulse, weve been given Light Up the Stage and, more recently, Reckless Impulse
Since then, double-faced cards that transform under specific conditions have become semi-regular sights in Magic
The History of Transform in MTG Transform first came out in the fan-favorite Innistrad set in 2011, partly to represent the population of the plane turning into the monsters that the horror-inspired world was home to
Its also really easy to break, as all you need is two creatures that can flicker each other, which not only produces infinite +1/+1 counters on your creatures, but also scales firebending up to make infinite mana when Zuko attacks
