SELECT USERNAME
FROM DBA_USERS U
WHERE EXISTS ( SELECT 1  FROM DBA_OBJECTS O WHERE O.OWNER = U.USERNAME )
AND USERNAME NOT IN ('SYSTEM','SYS')   
ORDER BY USERNAME;                    
--217 ROWS SELECTED.

SELECT OWNER, OBJECT_TYPE,COUNT(OBJECT_TYPE) 
FROM   DBA_OBJECTS
WHERE  OBJECT_TYPE = 'TABLE'  
GROUP  BY OBJECT_TYPE ,OWNER
ORDER  BY 1 ASC;
--190 ROWS SELECTED.

SELECT OWNER USUARIO
      ,OBJECT_TYPE OBJETO
      ,COUNT(OBJECT_TYPE) TOTAL
FROM   DBA_OBJECTS
GROUP  BY OBJECT_TYPE,OWNER
ORDER  BY 1 ASC;