The Blue Wind Rider can be purchased for 50 from the following vendors
Armored Blue Wind Rider - Wowpedia - Your wiki guide to the World of Warcraft
Warden - Warcraft Wiki - Your wiki guide to the World of Warcraft
I've noticed a recurring lore question some people have is: What
Wind Rider Cub (NPC) - Wowpedia - Your wiki guide to the World of
Spectral Wind Rider - Spell - World of Warcraft
Gryphon Rider (Warcraft III) - Wowpedia - Your wiki guide to the
Swift Windsteed - Item - World of Warcraft
Blue Wind Rider - Wowpedia - Your wiki guide to the World of Warcraft
Cliffside Wylderdrake - Warcraft Wiki - Your wiki guide to the World