Ultima IV: Quest of the Avatar/Side Quests

All information to get the rare items is already in the game, if the Stranger talks with every character. Although the NES version has simplified dialogues, most information is still found in the same towns and also at the same pubs.

The magical wheel
This item is not included in the NES version.

More spells
In the NES version, there are more spells to be found: sleep, reflect, negate, destroy, jinx, squish, tremor and defeat.

NES-only items
In the NES version the party can include up to four companions, while the other ones can be left at the hostel in Castle Britannia. Because of this, some items were created to upgrade two characters considered weak, otherwise players would have seldom used them.
 * The sheep flute for the Shepherd: it allows to cast "Sleep" on all opponents unlimited times with no MP consumption;
 * the humble robe for the Shepherd: it is one of the best armor in the game, only inferior to the Mystic Armor;
 * the dragon scale to create the legendary axe for the Fighter: it is the second best melee weapon in the game, only inferior to the Mystic Sword.

The flute and the robe are found in Magincia ruins, but they're not available at the beginning of the game because they are protected by poison fields and a locked door, respectively.

The scale is found in the Serpent's mountains, that can only be reached by air. If it's brought to Zircon of Minoc, he will use it to create the legendary axe.