The two cards you put on top of your library can be from the four you just drew or ones that were already in your hand
Of course, you could also invest that mana into something like Heroic Intervention to protect your own creatures from being destroyed
Sidisi, Brood Tyrant Sidisi was designed to go into a deck that enables graveyard shenanigans, as that is what her clan likes to do
As with other board wipes, the best way to use Sunder is to pair it with a powerful creature or other threat that is capable of winning the game on its own
She makes the player choose between giving a single +1/+1 counter to another creature, creating a Food Token, or creating a Treasure Token
Ajani, Nacatl Pariah / Ajani, Nacatl Avenger Ajani, Nacatl Pariah has shown itself to be a wildly busted card