Cave of Wonders Diamond is an Agrabah item. It appears in the fifth episode of the sixth season. Jasmine hires Aladdin to get the mysterious "Diamond in the Rough", believing it can help them break Jafar's hold on the Sultan. They find the diamond in the Cave of Wonders, but when it dissolves in a puff of magic smoke, Jasmine realizes that the real Diamond in the Rough is actually Aladdin.
Golden Scarab of Agrabah
Golden Scarab of Agrabah is an Agrabah item. It appears in the fifth episode of the sixth season. It was given to Jasmine's family by the people of Agrabah many generations ago as a gift for freeing the kingdom from darkness. It is now one of the great treasures of Jasmine's kingdom.
Eye of the Storm is an Enchanted Forest item. It appears in the fifteenth episode of the fifth season. Its is a much sought-after blue sapphire, and countless sailors have lost their lives trying to find it. Hades offers the stone to Liam Jones, in exchange for letting his cargo ship sink so Hades can have the crew's souls, except for him and his brother Killian, who will be saved. Liam makes the deal, and drives the ship right into a storm. Liam then uses the stone to get him and his brother their dream jobs in the royal navy.
Hercules' Medals are Enchanted Forest items. They appear in the thirteenth episode of the fifth season. The medals show motifs from the Labors of Hercules: The Nemean Lion, the Lernaean Hydra, the Ceryneian Hind, the Erymanthian Boar, the Augean stables, the Stymphalian Birds, the Cretan Bull, the Mares of Diomedes, the girdle of Hippolyta, the cattle of the monster Geryon, and the apples of Hesperides. The final labor, Cerberus, is missing, since Hercules hadn't faced him yet.
Jack's Sword is an Enchanted Forest item. It first appears in the sixth episode of the second season. With the sword laced in poison, Jack wields this weapon to attack and kill numerous giants, including Arlo, and then meets her own demise after being stabbed by her own sword. Both Jack's weapon and corpse remain in the Giants' Lair for decades. ("Tallahassee", "Tiny")
Lily's Necklace is an Enchanted Forest item. It first appears in the nineteenth episode of the fourth season. Lily always wears it as it was her only memory from her birth mother. When she was a teenager, Lily lost her necklace as she run away from her criminal boyfriend. She asked Emma to take back the necklace for her. Eventually, Lily is reunited with Maleficent, who tells her that the necklace is a piece of her dragon egg, but also her only clue about her father. ("Lily", "Operation Mongoose Part 2")
Mirror of Souls
Mirror of Souls is an Enchanted Forest item. It appears in the seventeenth episode of the fifth season. If somebody has evil in their soul, it will be revealed in the mirror's gaze, in which the person's eyes will glow with demonic fire. The mirror was located about an hour's ride away from Belle's castle, and she eventually recovers it. Later, through the mirror's reflection, Belle discovers that Gaston has evil in his soul.
August's Cure is a Land Without Magic item. It appears in the eighteenth episode of the second season. It is a vial of a red magic potion sold to August Booth by the Dragon to prevent him from turning back into wood. Tamara gets hold of the potion and runs technologically advanced tests on it, only to discover it contains no elements from this world, which helps her realize it's actual magic.
Ice Magic Neutralizing Candle is a Storybrooke item. It appears in the seventh episode of the fourth season. It is a candle-shaped spell that can supposedly neutralize Ice Magic. To use it, someone must magically light the candle and then blow over it. However, there is no evidence that the spell actually works, as Emma fails to neutralize Elsa's and Ingrid's magic.
As Wish Realm Hook points out, this will also seek out alternate versions of the same person. This summoned him as well.
Neverland Sand Clock
Neverland Sand Clock is a Neverland item. It appears in the eight episode of the third season. It is a giant hourglass inside Skull Rock created when Peter Pan made the decision to stay in Neverland. The hour glass represents the magic fueling Pan's youth. Once the sand runs out, Pan will die, unless he finds another way to preserve his youth.
Magic Paper is a Wonderland item. It appears in the second episode of the spin-off. It is a special kind of paper Cyrus picked up on his many travels. It can be magically animated and folded, and messages can be written on it simply by using a finger. The paper smells like a rose.
Sands of Morpheus is an item of unknown origin. It first appears in the first episode of the sixth season, and is a special kind of enchanted sand that can be used to enter a person's Dream World when sprinkled over their sleeping body. It can be found in the Temple of Morpheus. When used on someone in the Sleeping Curse, the persons soul that is supposed to be in the Netherworld will be transported to his/her Dream World for a limited time, if that time expires he/she will be transported back to the Netherworld. ("The Savior", "The Black Fairy")