Modifiers matching equid:

• extinct,
• large,
• wild,

Simple categories matching extinct:

• relative,
• beast,
• mammal,
• vertebrate,
• animal,
• bird,
• human,
• amniote,
• fauna,
• dinosaur,
• predator,
• archosaur,
• organism,
• ratite,
• creature,
• herbivore,
• reptile,
• giant,
• equid,
• plant,