That being said, Tara Larsen, one of the crew-members on Supernatural, tweeted a picture of one of Castiel's wardrobe tags...and it'd be remiss of me not to preserve this information.
The tag is from The Man Who Knew Too Much (6x22), but as Castiel very rarely wears anything other than his standard suit and trench-coat, this could be seen as a listing of Castiel's wardrobe from Lazarus Rising (4x01) to Hello, Cruel World (7x02):
The Tag reads:
TRENCHCOAT: Tan cotton traditional long [...] breasted, buttoned straps at wrist, belt, worn in & [...] "J.C. Penny" 40R
SUIT: Charcoal grey wool 2-pc, 3 button, flap pkts, no vent. 2-pleat pants "Joseph & Feiss" 42L.
SHIRT: White cotton L/S dress shirt, single chest pkt "Claiborne" L (16/34)
TIE: Dk. blue fine diagonal self-stripe, broken down "Calvin Klein"
BELT: Black leather dress belt w/edge stitching, silver buckle "PB1153-04" 36
SOX: Black wool dress socks.
SHOES: Black matte leather pull-on Aussie outback ankle boots w/elastic inserts at ankle, squared toes, black rubber. 1.5" heeled soles. "Blundstones" 12 (AUS 11).
In Season 8, once Castiel gets out of Purgatory, he returns to his classic trench-coat and suit look. During a set visit, a reporter tweeted a picture of his wardrobe tag from 8x23 Sacrifice:
This tag is much easier to read, but just in case anyone needs it typed out:
Trenchcoat: Tan traditional long trench [...] breasted, wide notched lapels, yoke capelet on back [...] straps at wrist, belt, worn in and dirtied "J.C. Penny"
Suit: Charcoal grey heathered fine wool 2-pc., 2-[...] w/notched lapels, lower flap pkts, 4 button sleeves, [...] back vents, burgundy lining, flat front pants w/side seam [...] buttoned welt back pkts "Wilke Rodriguez" 42L/36
Shirt: White fine stretch cotton L/S dress shirt. no pkts, cream pearly shirt buttons "Banana Republic Slim Fit" M (15-15.5)
Tie: Dk. blue fine diagonal self-stripe, broken down, "Calvin Klein"
Belt: Black leather dress belt w/edge stitching, silver buckle "PB1153-04" 36
Shoes: Black matte leather pull-on Aussie outback ankle boots w/elastic inserts at ankle, squared toes, black rubber 1.5" healed soles "Blundstones" 12 (AUS 11).