There are a ton of decks that both my Mom and I have discovered at garage sales!
(Although I will admit my Mother is so much better at it!)
Let's see...tiny RWS, Tarot Balbi, Tarot of the Witches, Tarot Nova, Southwest Sacred Tribes, Cat People, 1JJ Swiss, Mythic, Grand Tarot Esoterico, Hoi Polloi, ...there might be a few others that I am forgetting!
Also...lots of Oracle decks..like different Sibillia decks and my Sakura CLOW cards!
This has been over the course of the last 15 or so years...and I don't think we payed more than $2 for any of these.
And I can't even count the number of books...on tarot, new age, and occult subjects that we have found!
I do have to add...that my Mother goes to garage sales for a living! It's not her job...it's her calling!