Items, NPCs, quests, objects and spells of patch 1.12.1, read live from the realm itself.

Elixir of Greater Agility

NPC Level Zone Chance

Winterfall Ursa 57 - 58 Winterspring 0.02%

Scarshield Worg 53 - 54 Blackrock Spire 0.02%
Container Chance

Cenarion Circle Cache 12.6%
Source How Reagents

Elixir of Greater Agility Alchemy (1) SungrassGoldthornCrystal Vial

NPC	Level	Zone	Chance
Winterfall Ursa	57 - 58	Winterspring	0.02%
Scarshield Worg	53 - 54	Blackrock Spire	0.02%