The DBA_TYPES view provides information about all object types in the database.

ownerTEXTThe owner of the object type.
schema_nameTEXTThe name of the schema in which the type is defined.
type_nameTEXTThe name of the type.
type_oidOIDThe object identifier (OID) of the type.
typecodeTEXTThe typecode of the type. Possible values are: OBJECT, COLLECTION, OTHER
attributesINTEGERThe number of attributes in the type.