One, for example, gives the player who rolls Chaos a 7/7 colorless Eldrazi token which forces a defending player to sacrifice a permanent when it attacks
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
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
This list tries to mix things up a bit, with Fires of Invention allowing you to threaten the combo at any moment even if you only have four lands on the battlefield