Check the table which has no index present in Oracle

Check table has no index for all the schema present in Oracle Database except sys or system

select 	OWNER,TABLE_NAME
from 
(
select 	OWNER,TABLE_NAME 
from 	dba_tables
minus
select 	TABLE_OWNER, 
TABLE_NAME 
from 	dba_indexes
)
Info_noindex
where	OWNER not in ('SYS','SYSTEM')
order 	by OWNER,TABLE_NAME;

Find the table which have no index present for particular schema or owner

select 	OWNER,TABLE_NAME
from 
(
select 	OWNER,TABLE_NAME 
from 	dba_tables
minus
select 	TABLE_OWNER, 
TABLE_NAME 
from 	dba_indexes
)
Info_noindex
where	OWNER = 'HR'
order 	by OWNER,TABLE_NAME;