Leopard

Leopards were a type of large predatory mammal native to Africa on Earth. They usually had spotted coats like jaguars.

Encounters with leopards
While attempting to hide in a tree from the Quarks, the Second Doctor and Jamie found a leopard already in it. They catapulted the leopard out of the tree, giving them time to flee while the Quarks fought with the leopard. (TVC: Jungle of Doom)

In ancient Rome, leopards were kept as a part of a menagerie that included giraffes, elephants and a wide range of other, chiefly African animals. Some of the beasts were kept for hunting and others were used to fight prisoners in local amphitheatres. The Tenth Doctor once found himself incarcerated in a Roman prisoner and forced to participate in one of these events in an arena. Leopards were the final round in a series of trials that involved lions, tigers and bears. After a harrowing few minutes, he helped some of his fellow prisoners escape the leopards and the amphitheatre, to freedom. (NSA: The Stone Rose)

The Great Old Ones showed Erimem that her father, prior to his death, had given the order to Pyran that she should be bound and thrown to the leopards on her next birthday. (BFA: The Roof of the World)

Somerset's leopards were a genetically enhanced version of the cat employed for domestic functions. Qixotl created his own kind. They could record information that could later be read from their urine. They also consumed people who weren't on his guest list. (EDA: Alien Bodies)

Leopard skins
The leopard's spotted pattern was a common motif in art, clothing and decoration.
 * Iris Wildthyme owned a leopard-skin coat which once surprised her by attacking a magician. (BFIW: Roubh Magic)
 * According to the Fifth and Seventh Doctors, the TARDIS had a pre-programmed leopard skin "desktop theme." (BFA: Klein's Story, DW: Time Crash)
 * Ixta's formal wear was a leopard skin costume and mask. (DW: The Aztecs)

Cultural references to leopards
The Veiled Leopard was the name of a diamond once owned by Erimem. (BFA: The Veiled Leopard) In western Africa, a group called the leopard society kept secret knowledge of the Great Old Ones. (NA: White Darkness) Red Leopard was a crime family. (BNA: Ghost Devices)