Deck Your Collection (Season 1)

Final reward for beating them all should have been a closet to store all these shirts...

You get 50 [currency=396] after defeating every boss.
And, you get a special shirt for every boss, PLUS, a final shirt for the achievement.

And, here's the list of the differents cards, and how to get them:

• 
  
• [item=97978]
  This card is obtained by dancing (/dance) with [npc=71082], who is located in Kun-Lai Summit (coords are 65,60). After the emote, he gives you the card, and the quest associated is [quest=32837].

• 
  
• [item=97990]
  This card is obtained in the event Battlefield: Barrens. You can buy it at the cost of one [item=97849], and the seller is [npc=71226], who is located in the Razor Hill Watchtower (49,40), Durotar.The quest associated with this card is [quest=32859].

• 
  
• [item=97980]
  This card is obtained by doing the daily quest The Burlap Grind. Just smash the hozens until you get it. The quest associated with this card is [quest=32841].

• 
  
• [item=97981]
  This card is obtained by fishing in the different Pandaria pools. The quest associated with this card is [quest=32843].

• 
  
• [item=97982]
  This card is obtained by getting the loot bag after finishing random scenarios [item=98133]. Not confirmed if it is also contained in Heroics loot bags, or daily loots bags. The quest associated with this card is [quest=32845].

• 
  
• [item=97983]
  This card is obtained after defeating Bruce, the first "Boss" of the Brawler's Guild. If you have already defeated him, you can buy his card ([item=93823]) for a rematch. The quest associated with this card is [quest=32847].

• 
  
• [item=97984]
  This card is obtained after defeating the new elite battle pet ("Doppy"), who is located in northern Icecrown (48,14). The quest associated with this card is [quest=32849].

• 
  
• [item=97985]
  This card is obtained after opening the [item=86623] from [npc=43929]. The quest associated with this card is [quest=32851].

• 
  
• [item=97979]
  This card is obtained by looting the Caravan Supply Box ([item=97954]) in the Battlefield: Barrens. There have been reports that this card is also contained in the loot bags [item=98133]. The quest associated with this card is [quest=32839].

• 
  
• [item=97988]
  This card is obtained from harvesting crops in your farm. The quest associated with this card is [quest=32857].

• 
  
• [item=97986]
  This card is obtained by digging Tol'vir Digsites. Also, there have been reports that it can be contained in [item=87539]. The quest associated with this [quest=32853].

• 
  
• [item=97987]
  This card is contained in [item=93724], which is the reward of the following quests: He Shoots, He Scores!, It's Hammer Time, Target: Turtle, The Humanoid Cannonball and Tonk Commander. The quest associated with this card is [quest=32855].
  
  

The letter from Bizmo that comes with the shirt ([item=98543]):

"Let's take a quick inventory: You've defeated a shark, a robotic crocolisk, a pile of ooze, a pair of penguins, and a whole roomful of deadly brawlers from around the world.

Yeah, I'd say you've earned a shirt."