WB blocks elemental attacks in addition to (normally) unblockable attacks, such as Smite. Here's a list of elemental attacks we've verified to be Blockable or Unblockable with WB. Note that all of the below are Unblockable with normal Shields. Elemental skills denoted with a "?" are unconfirmed:

Class-based elemental skill list (some monster still use the below skills. e.g.. Inferno for Fetish Shaman)

Phoenix Strike/Chain/Lightning/Sentry - Blockable Wake of/Inferno - Blockable Skeleton Mage Missiles - Blockable Teeth - Blockable Bone Spear - Blockable Bone Spirit - Blockable Poison Nova - Blockable Smite - Blockable Fist of the Heavens - Blockable Firebolt/Hydra - Blockable Fireball - Blockable Blaze - Unblockable Firewall - Unblockable Phoenix Strike/Meteor - Blockable (Meteor impact itself is blocked, not residual flames) Claws of Thunder/Nova - Blockable Phoenix Strike/Ice Bolt/Frozen Orb - Blockable (Ice Bolts are blocked with Frozen Orb, not the Orb itself) Blizzard - Blockable Molten Boulder - Unblockable Artic Blast - Blockable Fissure - Unblockable Hurricane - Blockable

Monster-based elemental skill list

Tainted Lightning Ball - Blockable (no 'tink' sound) Sand Maggot/Frog Demon/Tentacle Beast Poison Missile - Blockable Greater Mummy Unholy Bolt - Blockable Oblivion Knight Missiles - Blockable Fanatic Enslaved Explosion – Blockable

Demon Imp Fire Missile - Blockable Succubi Blood Star - Blockable Baal Hoarfrost - Blockable (once one successful block is achieved, you will no longer take damage or be knocked back by the same Hoarfrost)

In addition, WB chance to block remains the same when you run, unlike Shield block, which decreases to 1/3, when you run.