Here, the strategy is based on heroes, with card effects and abilities bolstering characters with the hero attribute
Imagine your defender being like a wall, flying creatures can just fly over it, unless it has some way of reaching them
You can always search the card name on TCGplayer
In both cases one of your creatures goes nuclear and deals damage equal to its power to all other creatures
Unfortunately, that hype has also given way to some insane market price inflation of unopened product, with a box of Collector Boosters having just recently crossed the $1,000 mark from its initial MSRP of $499.99
8 Split Up A New Spin On The Sweepers Of Old Four mana is where sweepers tend to be costed - anything less would be obscene and anything more tends to be a little slow (though in the latter case, with the right additional effects, it can still work)