They all prevent damage you take, save for Goblin Fog, which for some reason doubles it
The Best Card Draw in Blue Since the beginning of days, when Richard Garfield, Ph.D
I For each opponent, up to one target noncreature artifact they control becomes a 0/4 Wall artifact creature with defender for as long as you control this Saga
The included instructions even have a demo game you can play with the included decks - sort of an on-rails experience that serves to show you all the key moves in an interactive fashion
If your opponent is reluctant to engage in combat, and they should be, look into enrage and pingers to ensure you give your opponent at least 1 point of direct damage
This iterative process of testing and refinement is how new, innovative decks are born and rise to the top of the metagame