Efficiency

Level 5 of the Dungeon
(0, 0, D:5)
  a +0 trident

Level 6 of the Dungeon
(0, 0, D:6)
  10 gold pieces
(0, 1, D:6)
  10 gold pieces
(8, 17, D:6)
  19 gold pieces
(23, 22, D:6)
  22 stones
(24, 20, D:6)
  a +0 hand axe
(29, 15, D:6)
  a scroll of identify