Marrow-Gnawer's ability can be activated at instant speed, meaning you can use it before the turn cycle comes back to you, so all the Rats it makes will be able to attack without summoning sickness
The Brothers' War for Magic: The Gathering brings in a slew of new spells that tells the story of Mishra and Urza
Gift Spells Bloomburrow introduced us to an entire group hug mechanic with the gift ability
By tapping another creature, you can add a number of charge counters to the permanent with Station equal to the creatures power and once they reach a certain threshold, the station will come alive, so to speak
vAdding a new range of strategies through combos never seen before
I have seen far more chump attacking swinging creatures into a larger blocker in this set than any other I remember, and I have let far more of those attacks go through