I always loved the 1977 animated "The Hobbit" from Topcraft. I can't find many specific details on the creature design but the crew included Toru Hara, Tsuguyuki Kubo, Hidetoshi Kaneko and Kazuko Ito whose work you might recognize in Thudercats among others.
Speaking of cats, I really loved how many Tolkien creatures appear feline in nature in Arthur Rackham Jr's version of the Hobbit. Smaug especially resembles a cat, but still withholds certain reptilian features of a serpent or crocodilian head shape.
