By tapping and untapping Snow Mercy a total of five times you can tap all creatures with a globe counter on it
This was one of the best combinations of flavor and gameplay mechanics that the Universes Beyond products have ever showcased in a precon
Focusing this theme on artifacts and enchantments and giving a ton of tools to support formats that care about either or both of these things gave the set a lot of tools to update existing archetypes, which is a huge improvement on stuff like Arcane, which generally didnt land or play well even with other Standard-legal sets at the time
Courser is somewhat better in the land ramp heavy decks as the extra shuffle lets you abuse the value and the information most
Then she drops the cost of everything by 1 generic mana, not just artifacts and enchantments which you might expect since she's an Artificer, but everything
Ill do the rest in alphabetical order, but the first Ill talk about is the card we previewed on this past Thursdays Commander Rules Committee (RC) stream at twitch.tv/commanderRC