While at CTN Animation Expo in 2018, I always check out the vendor booth, Animation Art Gallery, previously known as Wonderful World of Animation.
They're a merchant based in Culver City which sells original production art. Have a link, but beware your wallet.
Last year, I picked up this original animation drawing of Copper from the 1981 Disney film Fox and the Hound. I lovingly nicknamed the drawing "Sad Boy."
I also keep a very close eye on A Film LA where animator and animation historian, Hans Perk posts what is known as animation drafts for various films. They are documents which state which artist worked on what during animation production.
According to the recent draft of Fox and the Hound which was just published, the cute drawing of Copper I bought was animated by no other than the master animator Frank Thomas!
I have been looking for a Frank Thomas drawing for a while now, but as he is so revered in animation, finding an official drawing by him is challenging, and expensive. I was not expecting that I had already owned one, but when I found out I was beyond excited.