Several pieces of equipment in both games in the series bestow not power or statistic boosts, but the ability to use Psynergy spells that party member cannot use otherwise. All of these items bestow a Psynergy that can be used in the field, so they are called Utility Psynergy items.
Golden Sun items
Each item below, unless stated otherwise, will appear in the inventory of Isaac's party in The Lost Age if that game is played without password-enhancement.
Carry Stone: The Carry Stone is acquired from a chest in the beginning portion of Venus Lighthouse (the part that is accessible before entering Lalivero). Use Reveal at the carving on the wall in the second room and take the now-visible staircase down to a platform with the treasure chest containing the Carry Stone. It bestows the Carry Psynergy, and can move light objects through the air, even over boundaries that Move cannot overcome.
Catch Beads: The Catch Beads are automatically given to Isaac when he leaves Vale to depart on his quest. The Catch Psynergy it bestows allows Isaac to grab and retrieve remote items visible two squares away, such as Apples and Nuts growing on trees and Keys on platforms in Crossbone Isle. It is one of the utility Psynergy items that will be in Isaac's Party, regardless whether or not the password transfer is used.
"After you beat Collosso speak to Babi, you notice that Babi goes left. Follow him. On a table beside his bed, you see the Cloak Ball. Walk up to it and press A. Babi will talk for a bit then let you have the Cloak Ball."
It allows the user to use the Cloak Psynergy, which conceals the user to become effectively invisible when in shadowy places. Its primary uses are in Lunpa Fortress (it is vital to a big sidequest) and in Crossbone Isle (required to progress past floor 4 and get the Storm Gear). It is one of the utility Psynergy items that won't be in Isaac's party in The Lost Age if the game is not password-enhanced, though there is no use for Cloak in that game.
Douse Drop: the Douse Drop is gained after defeating the Killer Ape in Mogall Forest. It bestows the Psynergy Douse, which makes water rain down upon an object. In The Lost Age, Piers already has this Psynergy at his disposal, regardless of his class.
Frost Jewel: The Frost Jewel is obtained by defeating the first Living Statue in the Altin Mines. It bestows the Psynergy Frost. Even though the party already has Frost at their disposal, it can be used quite effectively while helping Isaac at Colosso, and in any case lets the player use Frost without having to first put all of Mia's non-Mercury Djinn on Standby.
Halt Gem: the Halt Gem is acquired in the cave on the outskirts of Vale. It bestows the Psynergy Halt, which stops anything in its tracks. Although it can be transferred to The Lost Age, it has no use whatsoever in the sequel. In the first game, it is really only used to acquire two Djinn, and the Storm Gear.
Lifting Gem: The Lifting Gem is found in a treasure chest after defeating the Hydros Statue in Altin Mines. It bestows the Lift Psynergy, which gives the Adept it is equipped to the ability to lift large boulders off the ground.
Orb of Force: The Orb of Force is received from a treasure chest after passing the test in Fuchin Falls Cave. It bestows the Psynergy Force, which shoots a shockwave into an object. It can only be obtained in The Lost Age by transferring data over from Golden Sun, and can only be used twice effectively.
Golden Sun: The Lost Age items
Burst Brooch: The Burst Brooch is an item found at the top of Tundaria Tower, and is required to complete the dungeon. It bestows the Burst Psynergy to the Adept who equips it, and the Psynergy is used to blow open many cracked surfaces found throughout the game.
Cyclone Chip: The Cyclone Chip is acquired from the mayor of Madra, who gives it to Felix as a reward for capturing Briggs and helping prove Piers innocent. It bestows the Psynergy Cyclone, which blows away weeds that grow out of the ground and can be used on twisted platforms as a transporter in the Jupiter Lighthouse and Gabomba Catacombs.
Grindstone: The Grindstone, a relic that Lunpa the Righteous Thief found in some ruins back in his days as a thief long ago, is acquired from King Hydros after he explains how the absence of Alchemy has caused the world to dissipate. It bestows the Psynergy Grind, but unlike other utility Psynergy items, the Grindstone is the only one that can be equipped to only one type of Adept (this case being Venus). Grind pushes a large, upright object down, usually into the sea or through a hole.
Hover Jade: The Hover Jade is given to Felix and his party by Moapa when they return the Shaman's Rod to the Shaman Village, and then defeat Moapa in a competition at Trial Road. When equipped it bestows the power of Hover, which is a secret flying Psynergy that only the people of Anemos knew about. It allows the user to float in the air over special glowing purple floor tiles.
Lash Pebble: the Lash pebble is acquired from Master Poi after overcoming the trial at the Kandorean Temple, and is the first utility Psynergy item gained in The Lost Age. It bestows the Psynergy Lash, which can be used to tie coiled ropes to far away spikes, which can then be climbed.
Pound Cube: The Pound Cube is obtained from the Mars Djinni Cannon, after a somewhat complex puzzle found at Dehkan Plateau (note that the Djinni does not have to be defeated to acquire the Pound Cube). It bestows the Psynergy Pound, which drives columns into the ground.
Scoop Gem: The Scoop Gem is acquired from the King Scorpion after defeating it in the Yampi Desert. It bestows Scoop, allowing you to dig up soft patches of ground that might have an item in them. These items include Game Tickets, Coins and Herbs.
Teleport Lapis: The Teleport Lapis is obtained from a treasure chest in Mars Lighthouse. It bestows the Teleport Psynergy, and can be used on stretches of ground that have a circular mural present, and will teleport the party from one to another. Teleport can also be used on the World Map, and can transport the party to any town or city they have already visited.
Tremor Bit: The Tremor Bit is obtained from a treasure chest in the Madra Catacombs, which can be accessed before the party learns Reveal. Tremor shakes the ground, and can knock down many big obstacles so the player can get whatever it was obscuring.
Golden Sun: Dark Dawn items
Grip Crystal: The Grip Crystal is found in Konpa Ruins and can only be equipped by Venus Adepts. It grants the Grip Psynergy, which can be used to cross some gaps, pull certain levers, and obtain distant items (similar to the Catch Psynergy).
Sand Prince Stone: The Sand Prince Stone is won from the Sand Prince in the back room of Ayuthay's Alchemy Well. It can only be equipped by Mars Adepts, who acquire the Arid Heat Psynergy series. Arid Heat can be used to evaporate the water in certain basins, typically lowering the local water level in the process, making it similar to the Parch Psynergy.
Insight Glass: The Insight Glass is acquired upon completion of the Barai Temple and never appears in the player's inventory, instead immediately merging with Amiti and granting him the Insight Psynergy, which is used to provide hints for solving puzzles and for spying on the emotions of NPCs.
Ice Queen Stone: The Ice Queen Stone is won from the Ice Queen in Harapa Ruins. It can only be equipped by Mercury Adepts, who acquire the Cold Snap Psynergy series. As a utility Psynergy, Cold Snap is functionally identical to the Frost Psynergy, turning puddles of water into pillars of ice.
Crush Tusk: The Crush Tusk is acquired after the defeat of the Sludge in the Phantasmal Bog. It can only be equipped by Mars Adepts, who acquire the Crush Psynergy. Crush is similar to the Pound and Burst Psynergies, allowing the player to destroy cracked objects and push pillar-like objects into the ground. It's usable in battle.
Slap Glove: The Slap Glove is given to Matthew by Ryu Kou in Kolima Junction, although he takes it back shortly after the party defeats the Mountain Roc. It bestows the Slap Psynergy - also known naturally by Sveta - to whomever equips it. Slap can be used to wake up sleeping NPCs, knock down some objects, rotate large stone faces by slapping their large red noses, and can be used in battle. While the Slap Glove bestows Utility Psynergy, it's actually a Glove-class item.
Third Eye: The treasure of Warrior's Hill. It bestows the Search Psynergy upon Himi, waking her up from her psynergetic slumber in the process. While the Third Eye bestows Utility Psynergy, it's actually a Quest item rather than equipment. It disappears from the player's inventory during the previous event and merges with Himi's forehead (altering her appearance).