While they dont necessarily belong to a specific set, promo cards can hold great value, especially those linked to events, tournaments, or special products
This is simply the day/night set, and like dungeons before it, Im sure the moment-to-moment calculations around this mechanic will soon become second nature
This is optional, which means if you have some way of recurring your action cards from your discard, which emerald is very good at doing, then you dont have to take the benefit
11- Two-Mana Mana Rocks Whether its Arcane Signet, or some other Signet, some of the best ways to start ramping is just to drop an artifact on turn two that taps for mana
However, if you purchase a cheaper/smaller gem bundle gem/$ value is lower
Whether this tips our boilable friends into "actually overpowered" territory is another question, of course