Desolation of Smaug

Sweep the board and immediately deploy Smaug with the ritual mana — he survives (Dragon) and lands on an empty battlefield with haste.

If Head of the Hunt is on the battlefield, opposing creatures that would die to Desolation of Smaug are exiled instead and each produces a fresh 2/2 Wolf after the sweep, converting the mass removal into a new board for you.

After casting Spew Flame, Desolation of Smaug can sweep away smaller non-Dragons and provide four mana restricted to Dragon spells, letting three lands supply the remaining mana to cast Smaug from exile. Once in play, Smaug is also immune to Desolation's damage.

Desolation can clear away nearly every non-Dragon creature while leaving Smaug alive, and its four restricted mana can combine with one additional mana to cast Smaug immediately after the sweeper.

The Worm is a Dragon: it survives the 3-damage sweep, and the four ritual mana can cast it a full two turns early.

Each chapter can blink one of your non-Dragon creatures until the end step, protecting it while Desolation of Smaug clears the battlefield.

Casting Desolation of Smaug triggers the equipped creature's prowess before the sorcery resolves, giving it +1/+1 and potentially raising a 3-toughness creature out of range of the sweep.

The sweeper kills the 1/1 Pair, and its death trigger resolves afterward to create or rebuild a 4/4 Army on the otherwise-cleared battlefield.

After Desolation kills opposing non-Dragons, Supper for Spiders can convert all of those creature cards into Food artifacts under your control, extracting substantial value from the mass removal.

When Desolation kills Rhovanion Rampager, its death trigger rebuilds your board with a Goblin Army whose size equals the Rampager's power, leaving a threat after the battlefield is swept.

Casting Desolation triggers Gandalf, increasing him from 2/3 to 3/4 before the sorcery resolves so he survives the 3 damage while also dealing 1 damage to each opponent.

Desolation kills Front Porch Sentries, whose death trigger can give an opposing creature that survived the initial damage -1/-1, allowing the sweep to finish off a 4-toughness creature.

Concerted Care can give one of your non-Dragon creatures indestructible in response to Desolation of Smaug, preserving it through the sweep while opposing creatures die.

If Desolation kills one of your nontoken creatures, Part in Friendship immediately finds a replacement creature and may put it directly onto the newly cleared battlefield.

Desolation Prowler can pay 2 life to become 4/4 before Desolation of Smaug resolves, allowing it to survive the 3-damage sweep.

The Saga can create a 6/6 Dragon token, which is immune to Desolation's damage and lets you sweep away non-Dragon creatures while retaining a large flying threat.