Sam’s Black Buttoned Grey and Red (Purple) Plaid
I think this plaid shirt looks purple from a distance, but up close you can see that it’s actually grey with a bit of red. The most noticeable feature is its dark black buttons though.
In Meet the New Boss (7x01), Sam is wearing this shirt when he has his first visual hallucination in Bobby’s basement and then goes upstairs to watch the news about Cas.
In Blood Brother (8x05), we see Sam wear this shirt in a flashback to when his dog ran into Amelia’s motel room and he engaged her in a conversation about them both being drifters.
In Meta Fiction (9x18), Sam wears this shirt for the entire episode.
In Girls, Girls, Girls (10x07), Sam wears this shirt from the beginning of the episode until after they find the demon corpse in the brothel.
In Angel Heart (10x20), Sam wears this shirt when they send Claire off at the end of the episode.