showing current expensive queries plus most expensive object from execution plan:

select sa.sql_id,
  sp.child_number,
  sp.plan_hash_value,
  sa.parsing_schema_name SQL_PARSED_BY,
  sa.module,
  sa.action,
  sa.buffer_gets,
  sa.BG_PER_EXEC,
  sp.object_owner,
  --sp.object_name, -- this is the group factor
  sa.optimizer_cost,
  sp.cost COST_PER_EXP_OBJECT,
  round((sp.cost/sa.optimizer_cost)*100,0) OBJECT_COST_RELATION,
  listagg(OBJECT_NAME,', ') within group (order by object_name) MOST_EXPENSIVE_OBJECTS,
  sa.sql_text
 from
   (select sql_id,
     child_number,
     parsing_schema_name,
     module,action,
     buffer_gets,
     round(buffer_gets/nullif(executions,0),0) BG_PER_EXEC,
     optimizer_cost,
     sql_text
    from v$sql
    where parsing_schema_name <>'SYS'
   ) sa,
   (select sql_id, child_number, plan_hash_value, object_owner, object_name,cost,
     rank() over (partition by sql_id,child_number order by cost desc nulls last) costrank
     -- result set partitioned by sql and child to avoid duplicates 
     -- when same sql is executed by multiple users
    from v$sql_plan
    where (operation like '%INDEX%' or operation like '%TABLE%' or operation like '%MAT%')
     --and options='FULL' -- would limit to full table scans / full object scans
     and object_owner <>'SYS'
   ) sp
 where sa.sql_id=sp.sql_id
   and sa.child_number=sp.child_number
   and costrank=1 -- only use top costly object of each partition
 group by sa.sql_id,
   sp.child_number,
   sp.plan_hash_value,
   sa.parsing_schema_name,
   sa.module,
   sa.action,
   sa.buffer_gets,
   sa.BG_PER_EXEC,
   sp.object_owner,
   --sp.object_name, -- this is the group factor
   sa.optimizer_cost,
   sp.cost,
   round((sp.cost/sa.optimizer_cost)*100,0),
   sa.sql_text
 order by BG_PER_EXEC desc nulls last
 ;