A target opponent may have you draw a card, but if they don't, you may put a creature card with equal or lesser toughness from your hand directly onto the battlefield, cheating its mana cost entirely
Overall, Amethyst, Ruby, and Steel are more focused on attacking while Amber, Emerald, and Sapphire are more supportive, but each can be used to make interesting combinations and people can experiment with seeing what strategies work with their personal play style
Some cards (mostly creatures) don't have any information at all in this area (not counting italics text, which we'll get to in a moment), which means they don't have any special abilities
Additionally, the flavor of the Ice Age present in Ice Age and Alliances is a favorite of many of us here in Nashville
As you can see with Druids, that mostly meas messing with lands, either playing extra lands (which is pretty great) or turning those lands into creatures as most druids do once they get access to Awaken
