Sample:
select table_name, to_number(extractvalue(xmltype(dbms_xmlgen.getxml('select count(*) c from '||table_name)),'/ROWSET/ROW/C')) as RowCount from user_tables where iot_type != 'IOT_OVERFLOW' or iot_type is null;
Results:
OR
select owner, table_name, num_rows, last_analyzed from all_tables;