These can be unlocked through either capturing and/or transfiguration, if your following my Legendary Caretaker trophy solution, then almost all will be through transfiguration.
Memento's found can then be claimed on a related mirage board, for example Tamamohime's memento can be claimed on the Tama mirage
Ex A, B, C and Z are final bonus dungeons accessed near the intervention quest giver as doors from right to left
DLC Mirages are at the coliseum last on the list, and not included in this list
With "Do a lot of damage with one attack" everything is weak to bahamut's Mega Flare
Casting the Prismtunity requirements over and over again will increase the chances of success
As far as I know, all Mirages can be gotten from trading
Tama MiragesTama
Found: Story
Tamamohime
Found: Story
Yurugu MiragesYurugu
Found: Castle Exnine
Prismtunity: Inflict Oblivion
Kybui
Found: The Coliseum
Prismtunity: Inflict Doom
Chocobo MiragesSet 1Chocochick
Found: Wellspring Woods, The Coliseum
Prismtunity: Physical Attacks
Chocobo
Found: The Phantom Sands, The Coliseum
Prismtunity: Give Gysahl Greens
Mecha Chocobo
Found: Transfigure from Chocobo after Choclatte's Master Intervention quest
Set 2Black Chocochick
Found: The Watchplains
Prismtunity: Heal its HP
Hyperion
Found: Transfigure from Black Chocochick after The Black Chocobo Intervention quest
Siren MiragesSylph
Found: Story
Siren
Found: Story
Serafie MiragesSerafie
Found: Story
Diva Serafie
Found: Transfigure after A Smidge of Micro-Envy intervention quest
Carbuncle MiragesSet 1Mu
Found: Wellspring Woods, Pyreglow Forest
Prismtunity: Physical Attacks
Skull Eater
Found: The Train Graveyard, The Coliseum
Prismtunity: Give it Regen
Carbuncle
Found: The Coliseum
Prismtunity: Reflect magic back
Set 2Reaver Mu
Found: Pyreglow Forest, The Coliseum
Prismtunity: Fire Attacks
Nut Eater
Found: The Windswept Mire, The Phantom Sands
Prismtunity: Use magic boost moves on it (protect, shell, etc)
Goblin MiragesSet 1Goblin
Found: The Watchplains, Castle Exnine
Prismtunity: Lower its HP
Goblin Guard
Found: The Watchplains, Castle Exnine
Prismtunity: Give it Protect
Princess Goblin
Found: Transfigure from Goblin Guard after Where Art Thou, Smoochy-Poo? Intervention quest.
Set 2Red Cap
Found: The Watchplains, The Chainroad
Prismtunity: Do a lot of damage with one attack, he's weak to water -50 and light -25
Red Captain
Found: The Watchplains, The Chainroad
Prismtunity: Inflict Confusion on it
Malboro MiragesSet 1Mandragora
Found: Nether Nebula, The Watchplains
Prismtunity: Physical Attacks
Malboro
Found: The Windswept Mire, The Coliseum
Prismtunity: Inflict status ailments, he's weak to Oblivion -25, Slow -25 and Death/Doom -25
Set 2Korrigan
Found: Valley Seven, Castle Exnine
Prismtunity: Inflict sleep
Malboro Menace
Found: The Windswept Mire
Prismtunity: Inflict status ailments, he's weak to Oblivion -25, Slow -25 and Death/Doom -25
Giant MiragesSet 1Copper Gnome
Found: Nether Nebula, The Dragon Scars
Prismtunity: Lower its HP
Mythril Giant
Found: Big Bridge, Castle Exnine
Prismtunity: Use magic boost moves on it (protect, shell, etc)
Iron Giant
Found: Big Bridge secret area boss
Prismtunity: Use magic boost moves on it (protect, shell, etc)
Set 1Lead Gnome
Found: Valley Seven, The Chainroad
Prismtunity: Cast Shell on it
Chrome Giant
Found: The Train Graveyard
Prismtunity: Evade attacks from it
Golem MiragesSet 1Mini Golem
Found: Nether Nebula, The Dragon Scars
Prismtunity: Physical Attacks
Set 2Water Golem
Found: The Crystal Tower
Prismtunity: Do a lot of damage with one attack, he's weak to Thunder -50
Set 3Golem Head
Found: The Coliseum, transfigure after No One's Tools intervention quest
Prismtunity: Inflict Defense down
Flying Eye MiragesSet 1Floating Eye
Found: Nether Nebula, Saronia Docks
Prismtunity: Make it the last mirage standing
Ahriman
Found: Saronia Docks
Prismtunity: Inflict blindness
Set 2Blood Eye
Found: The Dragon Scars, Valley Seven
Prismtunity: Make it the last mirage standing
Buer
Found: The Coliseum, The Crystal Tower boss
Prismtunity: Inflict confusion
Ifrit MiragesSet 1Fritt
Found: Nether Nebula secret area rare spawn
Prismtunity: Fire attacks
Affrite
Found: Transfigure from Fritt
Ifrit
Found: Transfigure from Affrite or Gleefrit
Ifreeta
Found: Transfigure from Affrite or Gleefrit
Set 2Weeglee
Found: Ex C boss
Prismtunity: Fire attacks
Gleed
Found: Transfigure from Weeglee or Affrite
Gleefrit
Found: Transfigure from Ifrit, Gleed, or Ifrita
Shiva MiragesSet 1Bablizz
Found: Nether Nebula secret area rare spawn
Prismtunity: Ice attacks
Mishiva
Found: Transfigure from Shiva, Shivarina, Shivarly, or Bablizz
Shiva
Found: Transfigure from Mishiva or Shivver
Shivalry
Found: Transfigure from Mishiva or Shivver
Set 2Brrblizz
Found: Ex A boss
Prismtunity: Ice attacks
Shivverina
Found: Transfigure from Brrblizz, Shivver, or Mishiva
Shivver
Found: Transfigure from Shiva, Shivalry, or Shivverina
Ramuh MiragesSet 1Zapt
Found: Nether Nebula secret area rare spawn
Prismtunity: Thunder attacks
Zaphr
Found: Transfigure from Ramuh, Voultr, Zapt, or Ramewl
Ramuh
Found: Transfigure from Zaphr or Rairamuh
Ramewl
Found: Transfigure from Zaphr or Rairamuh
Set 2Joult
Found: Ex B
Prismtunity: Thunder attacks
Voultr
Found: Transfigure from Zaphr or Rairamuh
Rairamuh
Found: Transfigure from Ramuh, Ramewl, or Voultr
Fenrir MiragesSet 1White Nakk
Found: Icicle Ridge, The Coliseum
Prismtunity: Ice attacks
Fenrir
Found: The Coliseum
Prismtunity: Once per battle: reduce HP
Cerberus
Found: The Dragon Scars
Prismtunity: Use fire, ice, and thunder attacks
Set 2Black Nakk
Found: The Watchplains, Valley Seven
Prismtunity: Physical attacks
Elefenrir
Found: Transfigure from Black Nakk after Chosen by the Tribe intervention quest
Behemoth MiragesSet 1Babyhemoth
Found: Pyreglow Forest, Icicle Ridge
Prismtunity: Physical attacks
Behemoth
Found: Valley Seven, The Coliseum
Prismtunity: Once per battle: reduce HP
Behemonster
Found: Castle Exnine secret area
Prismtunity: Physical attacks
Set 2Kuza Kit
Found: Big Bridge
Prismtunity: Land a counterattack
Kuza Beast
Found: The Crystal Tower, Castle Exnine
Prismtunity: Land a counterattack
Moogle MiragesSet 1Moogle
Found: Pyreglow Forest, The Crystal Tower
Prismtunity: Heal its HP
Kupirate
Found: Saronia Docks, The Coliseum
Prismtunity: Once per battle: reduce HP
Set 2Kupicaroon
Found: Saronia Docks
Prismtunity: Inflict Berserk
Skull MiragesSet 1Deathskull
Found: Pyreglow Forest, Icicle Ridge
Prismtunity: Inflict Oblivion
Undead Princess
Found: Transfigure from Deathskull after Never Cross the Bridge intervention quest
Set 2Mordskull
Found: The Train Graveyard
Prismtunity: Inflict Oblivion
Set 3Metalliskull
Found: The Coliseum
Prismtunity: Inflict Oblivion
Claws MiragesSet 1Right Claw
Found: Pyreglow Forest, Icicle Ridge
Prismtunity: Once per battle: reduce HP
Set 2Left Claw
Found: Icicle Ridge, Big Bridge
Prismtunity: Once per battle: reduce HP
Cockatrice MiragesSet 1Cocktrice
Found : Pyreglow Forest, The Coliseum
Prismtunity: Physical Attacks
Valefor
Found: The Coliseum
Prismtunity: Earth attacks
Set 2Cocadrille
Found: Valley Seven, The Phantom Sands
Prismtunity: Inflict Poison
Nirvalefor
Found: Transfigure from Valefor or Cocadrille after The Sad Spiral intervention quest
Hydra MiragesSet 1Dualizard
Found: Pyreglow Forest, Saronia Docks
Prismtunity: Once per battle: reduce HP
Trihyde
Found: The Chainroad, The Coliseum
Prismtunity: Do a lot of damage with one attack, he's weak to ice -50 and earth -25
Tiamat
Found: The Coliseum
Prismtunity: Inflict Oblivion
Set 2Bihydra
Found: The Dragon Scars, Mako Reactor 0
Prismtunity: Once per battle, last Mirage standing
Ghidra
Found: The Crystal Tower
Prismtunity: Once per battle: reduce HP
Cactuar MiragesSet 1Cactuar
Found: The Phantom Sands, The Coliseum
Prismtunity: Inflict Slow
Gigantuar
Found: Mako Reactor 0
Prismtunity: Land a critical hit
Set 2Cactrot
Found: Pyreglow Forest
Prismtunity: Once per battle: reduce HP
Gigantrot
Found: Mako Reactor 0
Prismtunity: Cast Haste
Mimic MiragesSet 1Magic Pot
Found: Big Bridge
Prismtunity: Give an elixer
Mimic
Found: Saronia Docks
Prismtunity: Once per battle, reduce HP
Mimic Queen
Found: Transfigure from Mimic after I Hate Lightning! intervention quest
Set 2Magic Jar
Found: Pyreglow Forest
Prismtunity: Give it an elixer
Mimic Jackpot
Found: Transfigure from Mimic or Magic Jar
Prismtunity: Once per battle, reduce HP
Quacho MiragesSet 1Quacho
Found: The Sunken Temple, The Coliseum
Prismtunity: Heal its HP
Quacho Queen
Found: The Coliseum
Prismtunity: Heal its HP
Set 2Quachacho
Found: Icicle Ridge, Sunken Temple
Prismtunity: Heal its HP
Tonberry MiragesSet 1Baby Tonberry
Found: Big Bridge, Sunken Temple
Prismtunity: Physical attacks
Tonberry
Found: The Sunken Temple, The Coliseum
Prismtunity: Do a lot of damage with one attack, he's weak to thunder -50 and light -25
Tonberry King
Found: The Coliseum
Prismtunity: Once per batttle: reduce HP
Set 2Baby Paleberry
Found: Icicle Ridge
Prismtunity: Physical attacks
Paleberry
Found: The Crystal Tower, The Coliseum
Prismtunity: Light Attacks
Paleberry King
Found: The Chainroad
Prismtunity: Land a critical hit
Vampire MiragesSet 1Werebat
Found: Mako Reactor 0, The Train Graveyard
Prismtunity: Inflict Blindness
Vampire
Found: The Train Graveyard, The Coliseum
Prismtunity: Dark attacks
Vampire Prime
Found: The Coliseum
Prismtunity: Light attacks
Set 2Ice Bat
Found: Icicle Ridge, The Train Graveyard
Prismtunity: Inflict Blindness
Demivampire
Found: The Train Graveyard, Castle Exnine
Prismtunity: Reflect magic back at it
Flan MiragesMini Flan
Found: Saronia Docks, The Windswept Mire
Prismtunity: Physical attacks
Flan
Found: The Windswept Mire
Prismtunity: Physical Attacks
Flan Princess
Found: The Windswept Mire
Prismtunity: Face the Mirage with only one party member unstacked
Bismarck MiragesSet 1Sharqual
Found: Saronia Docks, The Sunken Temple
Prismtunity: Fire attacks
Mega Sharqual
Found: The Low Seas, The Coliseum
Prismtunity: Do a lot of damage with one attack, he's weak to thunder -50 and wind -25
Bismarck
Found: The Coliseum and transfigure after Finger-Wistle Crisis intervention quest
Prismtunity: Physical attacks
Set 2Nightsqual
Found: The Sunken Temple
Prismtunity: Inflict Sleep
Mega Nightsqual
Found: The Sunken Temple
Prismtunity: Bestow Bravery
Leviathan MiragesSet 1Sea Snake
Found: The Low Seas, The Sunken Temple
Prismtunity: Water attacks
Leviathan
Found: Transfigure from Sea Snake or Elasmos
Set 2Sea Serpent
Found: The Sunken Temple
Prismtunity: Water attacks
Elasmos
Found: Castle Exnine
Prismtunity: Do a lot of damage with one attack, he's weak to ice -100
Adamantoise MiragesSet 1Minimantoise
Found: The Low Seas, The Coliseum
Prismtunity: Once per battle: reduce HP
Adamantoise
Found: The Low Seas, The Coliseum
Prismtunity: Inflict Defense down
Set 2Flammantoise
Found: Valley Seven, The Coliseum
Prismtunity: Fire attacks
Dragon MiragesSet 1Spark Dragon
Found : The Dragon Scars, Valley Seven
Prismtunity: Inflict status ailments Confusion -25 or Sleep -25
Red Dragon
Found: The Dragon Scars, Valley Seven
Prismtunity: Land a critical hit
Set 2Mist Dragon
Found: Underground Prison
Prismtunity: Recover a lot of its lost HP at once
Holy Dragon
Found: Icicle Ridge
Prismtunity: Light attacks
Bomb MiragesBombino
Found: Mako Reactor O, Big Bridge
Prismtunity: Inflict Confusion
Bomb
Found: Valley Seven, The Crystal Tower
Prismtunity: Fire attacks
King Bomb
Found: The Coliseum
Prismtunity: Once per battle: reduce HP
Phoenix MiragesPhoenix
Found: Valley Seven
Prismtunity: Restore a lot of HP at once
Toad MiragesSet 1Water Toad
Found: The Windswept Mire, The Coliseum
Prismtunity: Inflict Berserk
Lucky Toad
Found: The Chainroad, The Coliseum
Prismtunity: Once per battle: reduce HP
Set 2Wind Toad
Found: The Crystal Tower
Prismtunity: Inflict Oblivion
Sphinx MiragesSet 1Manitcore
Found: The Chainroad
Prismtunity: Inflict Poison
Sphinx
Found: The Phantom Sands secret area
Prismtunity: Do a lot of damage with one attack, he's weak to water -50 and dark -25
Set 2Sandicore
Found: The Phantom Sands, The Coliseum
Prismtunity: Once per battle: last Mirage standing
Memocoleous
Found: The Phantom Sands
Prismtunity: Inflict Poison
Worm MiragesSet 1Sand Worm
Found: The Phantom Sands, The Crystal Tower
Prismtunity: Land a counterattack
Set 2Sea Worm
Found: The Sunken Temple, The Crystal Tower
Prismtunity: Once per battle: reduce HP
Magitek Armour MiragesSet 1Searcher
Found: Underground Prison, Mako Reactor 0
Prismtunity: Physical Attacks
Magitek Armour
Found: Underground Prison, Mako Reactor 0
Prismtunity: Once per battle: reduce HP
Death Machine
Found: Mako Reactor 0, The Coliseum
Prismtunity: Land a critical hit
Set 2Security Eye
Found: The Chainroad
Prismtunity: Once per battle: last Mirage standing
Magitek Armour A
Found: Castle Exnine
Prismtunity: Do a lot of damage with one attack, he's weak to thunder -25 and water -25
War Machine
Found: The Coliseum
Prismtunity: Land a critical hit
Set 3Death Searcher
Found: Castle Exnine
Prismtunity: Reflect magic back at it
Diabolos MiragesSet 1Imp
Found: Big Bridge, The Train Graveyard
Prismtunity: Inflict Confusion
Diabolos
Found: Transfigure from Imp
Set 2Garchimacera
Found: Mako Reactor 0
Prismtunity: Inflict Confusion
Minotaur MiragesSet 1Brothertaur
Found: Big Bridge
Prismtunity: Earth attacks
Minotaur
Found: The Chainroad, Castle Exnine
Prismtunity: Inflict Confusion
Set 2Sistertaur
Found: The Crystal Tower
Prismtunity: Once per battle: reduce HP
Asterius
Found: The Coliseum
Prismtunity: Inflict Berserk
Gilgamesh MiragesGilgamesh
Found: The Coliseum
Prismtunity: Inflict Berserk
Unicorn MiragesSet 1Unicorn
Found: The Crystal Tower
Prismtunity: Inflict status ailments Poison -50, Blindness -25 or Slow -25
Odin
Found: Transfigure from Unicorn
Set 2Nightmare
Found: The Train Graveyard
Prismtunity: Dark attacks
Squid MiragesSet 1Mindflayer
Found: The Crystal Tower
Prismtunity: Reflect magic back at it
Kraken
Found: The Coliseum
Prismtunity: Inflict Poison
Ultros
Found: Transfigure from Kraken after Freak of Nature and/or Operation Opera intervention quests
Set 2Squidkraken
Found: Castle Exnine
Prismtunity: Reflect magic back at it
Cenchos
Found: The Coliseum
Prismtunity: Reflect magic back at it
Titan MiragesSet 1Titan
Found: The Crystal Tower
Prismtunity: Land a critical hit
Madiun
Found: Transfigure from Titan, obtain the memento from The Five Cogna Lords: Figaro's miniquest (not in the twins room, intervention only)
its hard, you have to finish it in 20 moves total (10 for you, 10 for the ai) and no losses/deaths. Or ask me and I'll give it to you.
Set 2Iron Muscles
Found: Transfigure from Titan
Prismtunity: Inflict Defense Down
Magna Roader Mirages
Set 1Magna Roader (Purple)
Found: The Chainroad, Castle Exnine
Prismtunity: Once per battle: reduce HP
Set 2Magna Roader (Yellow)
Found: Castle Exnine
Prismtunity: Once per battle: reduce HP
Set 3Magna Roader (Red)
Found: Castle Exnine
Prismtunity: Once per battle: reduce HP
Omega MiragesSet 1Entom Guard
Found: Castle Exnine
Prismtunity: Fire Attacks
Omega
Found: The Coliseum
Prismtunity: Do a lot of damage with one attack, he's weak to thunder -100 and water -50
Set 2Entom Soldier
Found: Transfigure from Entom Guard
Prismtunity: Fire attacks
Omega Bane
Found: The Coliseum
Prismtunity: Do a lot of damage with one attack, he's weak to thunder -100 and water -50
Set 3Elite Entom
Found: The Coliseum
Prismtunity: Fire Attacks
Ultima Weapon MiragesUltima Weapon
Found: The Coliseum
Prismtunity: Do a lot of damage with one attack, he's weak to physical attacks
Supraltima Weapon MiragesSupraltima Weapon
Found: Story
Einhänder MiragesEinhänder
Found : The Coliseum
Prismtunity: Inflict Evasion down (Icebats ultrasonic)
XG MiragesXG
Found: Ex Z
Ifrit Star MiragesIfrit Star
Found : The Coliseum
Prismtunity: Fire attacks
Shiva Star MiragesShiva Star
Found : The Coliseum
Prismtunity: Ice attacks
Ramuh Star MiragesRamuh Star
Found : The Coliseum
Prismtunity: Thunder attacks
Leviathan Star MiragesLeviathan Star
Found : Intervention quest Ancestral Acrimony
Prismtunity: N/A
Bahamut Star MiragesBahamut Star
Found : Intervention quest The Demon Dyad Revealed
Prismtunity: N/A
Odin Star MiragesOdin Star
Found : Intervention quest A Clash of Swords
Prismtunity: N/A
Diabolos Star MiragesDiabolos Star
Found : Intervention quest When the Past Still Haunts
Prismtunity: N/A
Master Moogle MiragesMaster Moogle
Found : The Coliseum
Prismtunity: Use magic boost moves on it (protect, shell, etc)
Master Cactuar MiragesMaster Cactuar
Found : The Coliseum
Prismtunity: Inflict Evasion down (Icebats ultrasonic)
Master Tonberry MiragesMaster Tonberry
Found : The Coliseum
Prismtunity: Do a lot of damage with one attack, he's weak to earth -100
Mecha Chocobo Star MiragesMecha Chocobo Star
Found : The Coliseum
Prismtunity: Inflict berserk
Ifreeta Star MiragesIfreeta Star
Found : The Coliseum
Prismtunity: Fire attacks
Shivalry Star MiragesShivalry Star
Found : The Coliseum
Prismtunity: Ice attacks
Ramewl Star MiragesRamewl Star
Found : The Coliseum
Prismtunity: Thunder attacks
Quacho Queen Star MiragesQuacho Queen Star
Found : The Sunken Temple
Prismtunity: Heal its HP
Princess Goblin Star MiragesPrincess Goblin Star
Found : Cornelia Region
Prismtunity: Inflict Blindness
Ultros Star MiragesUltros Star
Found : The Coliseum
Prismtunity: Face the Mirage with only one party member unstacked
Undead Princess Star MiragesUndead Princess Star
Found : Ice Region outside Inn after Never Cross the Bridge intervention quest
Prismtunity: Light attacks
Giant Goblin MiragesGiant Goblin
Found: Story
Syldra MiragesSyldra
Found: Story
Grandfenrir MiragesGrandfenrir
Found: Story
Mega Red Dragon MiragesMega Red Dragon
Found: Story
Golden Flan MiragesGolden Flan
Found: Story
Black Mage MiragesBlack Mage
Found: Story
Magitek Armour B MiragesMagitek Armour B
Found: Story
Bahamutian Soldier MiragesBahamutian Soldier
Found: Story
Bahamutian Commander MiragesBahamutian Commander
Found: Story
Federation Guard MiragesFederation Guard
Found: Story