Wild Pets can be found throughout each continent, some being more rare than others. To collect one, you’ll need to engage it in battle (with one of your current pets), successfully capture it and win the battle if there are more than one to a team.

Here are the unique wild pets for each Cataclysm zone.

Nordrassil Wisp

Hyjal

Crimson Geode

Deepholm

Twilight Fiendling

Twilight Highlands

Tol'vir Scarab

Uldum

I couldn’t seem to find anything in Vashj’ir but will update when I do.