Ashen Rider
Ashen Rideras an obvious upgrade to Angel of Despair this one finds it’s way into Reanimator.  Not only do you gain the effect both in and out it also exiles the permanent instead of just destroying it.
Swan Song
Swan Song – as a very versatile answer card for just one blue mana this one finds its way into the sideboards of most blue based decks as a one of.
Toxic Deluge
Toxic Deluge – could be poised to be a premier sweeper as it is able to even get through all forms of protection.  Since it reduces toughness instead of dealing damage it is much more effective and can even be used to remove otherwise extremely difficult to answer cards like Emrakul or Progenitus.  Also is able to get in under Gaddock Teeg.
True-Name Nemesis – here’s the big new card…and what a card it is.  While not unbeatable by any means it is still something that needs to be answered almost immediately or you will find yourself facing the inevitable.  So much stronger then Progenitus, which is the only other card with a similar ability, because this protection still allows it to carry a Sword or Jitte.  Truly shines in Stoneforge decks.
Unexpectedly Absent
Unexpectedly Absent – hasn’t been showing up in numbers yet but has a high potential payoff.  This will frustrate many player when it unexpectedly shuffles away a key permanent in response to them cracking a fetch or casting a Stoneforge.
Baleful strix
Baleful Strix – this was an important card to get reprinted with the surge of Shardless BUG decks.
Bojuka Bog
Bojuka Bog – a key sideboard card for Knight of the Reliquary to tutor up against Dredge, Reanimator or other graveyard based strategy decks.
Goblin Sharpshooter
Goblin Sharpshooter – quite obviously an inclusion for many goblin decks.
Krosan Grip
Krosan Grip – the split second was a key element in how this card was used to combat against Counterbalance before Abrupt Decay, but it is still a very versatile sideboard choice regardless of the mana cost.
Lim-Dul's Vault
Lim-Dul’s Vault – while only appearing as a one of it is as always an amazing dig spell which can realistically set up two or three great draw steps at a minimal cost.
Thopter Foundry
Thopter Foundry – a classic combo piece when paired with Sword of the Meek.  Usually found for overlapping win conditions with Dark Depths combo.
Thoughtseize – has always been one of the best disruption spells because of it has very small limitations on targets.
Wrath of God
Wrath of God – although not uncounterable like Supreme Verdict it is still the all time classic sweeper.