In North Qeynos: Fippy Darkpaw spawns regularly in the newbie area in front of North Qeynos. He shouts a threat to the zone and then charges the Qeynos gate, only to be killed off by the guards outside.
In Brell's Rest: Fippy Darkpaw is a little more difficult. See this quest entry for event and loot information. A chest spawns with loot after completion of this event.
In Overseer:
This card comes as a bonus to the Overseer Starter Bundle in the DB Store under Overseer. Comes with 5 Overseer Agent Packs containing 3 Common Agents.
After you purchase you might have to log out and back in a couple times but it will eventually show in your /claim window as "Overseer Agent Pack" x 1