You can use Ambrosia Whiteheart to pick up permanents with good enters the battlefield triggers, save creatures from removal, or just pick up a land to guarantee another landfall trigger
The biggest offender here is wiping away graveyards, which cripples a lot of the recursion people would use to build back from a comprehensive board wipe like this
To determine the total cost of a spell, start with the mana cost or alternative cost you're paying (such as a flashback cost), add any cost increases (such as kicker costs), then apply any cost reductions (such as that of Danitha Capashen's last ability)
Clutch of the Undercity Cren, Undercity Dreamer Scourge of the Undercity Undercity Undercity Dire Rat Undercity Eliminator Undercity Informer Undercity Necrolisk Undercity Plague Undercity Plunder Undercity Reaches Undercity Scavenger Undercity Scrounger Undercity Sewers Undercity Shade Undercity Troll Undercity Upheaval Undercity Uprising Undercity's Embrace
In Temporal Forces, Creatures Inc
A nasty trio
