What beast is lying on the jade pendant? Kind of like a leopard.

According to the information you provided, this beast may be a badger.

In the traditional culture of China, badger is regarded as a symbol of good luck and happiness. On the jade pendant, the badger is often designed to lie on ruyi, because "badger" and "Huan" are homophonic, and this design means "happy ruyi". In addition, badgers are similar in appearance to leopards and may be mistaken for leopards.