Ok i get it now--they would be in the create new troops
The items also become available in your cities' shops. Too many are overpriced, but some are an absolute lifesaver for some types of heroes: the dodge cloak, the regeneration talisman, the speed amulet... If your opponent is fielding troops with a particular elemental attack, you may want to buy a Dragon skin cloak, an Ice warg pelt, etc...
Of course, mounts are essential to every hero.
And if you play without restores, you will want to stock up on healing items.