If I remember correctly, you can (SPOILER)Complete the CC Group sidequest before disc 4. Then get the Ragnorok, around the ship, there should be some CC members around (The Queen of Cards can be found with the Ragnorok). You can mod them into whatever, and play them to hopefully get your card back so you can do the same thing over and over. But it's been a long time since I've played FFVIII, so I'm not sure if this will completely work.

Anyways, other than refining the Laguna card, you can mug a Hero off of Seifer in Disc 2 when he's guarding Edea.

Holy Wars - Refine the Gilgamesh card.