Adder's Tongue

Adder's Tongue is a herb that can be gathered with Herbalism (400).

Source
Adder's Tongue is arguably the least common herb in Northrend aside from Frost Lotus. It only grows in Sholazar Basin, though it is found in abundance there.

Alchemy

 * Mighty Alchemist Stone
 * Elixir of Deadly Strikes
 * Elixir of Expertise
 * Elixir of Mighty Agility
 * Potion of Speed
 * Northrend Alchemy Research

Inscription

 * Azure Pigment
 * Icy Pigment