All Missable Items, Materia, Enemy Skills & Weapons in Final Fantasy 7
This page contains a complete list of all the items that you can permanently miss in Final Fantasy 7. As far as I know this page contains ever item that can be missed, including the most mundane ones that serve very little purpose. They're also in the order that you will pass them in the game, so if you'd like to look at this page as you play through the game to make sure you don't miss anything - you can!
Iron Bangle: You can only purchase this in the Sector 7 Weapon Shop at the start of the game
Ghost Hand: Stolen or dropped from Ghosts in the Train Graveyard or purchased from Battle Square before you get the Tiny Bronco
Battery: Obtained the second time you visit the Wall Market, they're used in climbing the wall
Elemental Materia #1: Given to you if you guess the password on the first try on Shinra Building 62nd floor
A Coupon, B Coupon & C Coupon: Obtained in Shinra HQ on Shinra Building 63rd floor
Enemy Skill Materia #1: Found in the chamber you met Red XIII inside at the Shinra Building
Elemental Materia #3: During the Kalm Flashback be sure to play the Piano and tell the party you "jammed on it". You can return here later in the game during Disc 2 when Tifa is in lead of your party for the Materia
Shinra Beta: Stolen from Marines on the Cargo Ship. Also dropped by enemies in the Underwater Reactor during Disc 2
Ifrit Materia: After defeated Jenova-Birth on the Cargo Ship this Materia will be available. If you leave the room you miss it forever
Ramuh Materia: This Materia is found inside of the Jockey Room in the Gold Saucer, you're in this area during your escape from Corel Prison. If you don't grab it when you're in the room you miss it forever
Vagyrisk Claw: Low level CMD Grand Horn bosses in the Fort Condor Side Quest drop this item. Also can be stolen from Bagrisk enemies
Added Effect Materia: Found inside the Cave of the Gi. Once you complete the dungeon you can never enter it again
Trine: The Materia Keeper boss in Mount Nibel is your first chance to learn this missable Enemy Skill
Yoshiyuki: When you first visit Rocket Town speak with the man outside the Item Shop three times and he will give you this item
Great Gospel: This is one of two rewards for the Arms Dealer Side Quest; Great Gospel is Aeris's Level 4 Limit Break
Luck Plus Materia: Obtained from the first part of the Temple of the Ancients dungeon
Morph Materia: Found in the boulder dodging puzzle in the first part of the Temple of the Ancients dungeon
Princess Guard: Found in the Temple of the Ancients dungeon, part of the clock puzzle. This is Aeris's Ultimate Weapon.
Umbrella: Prize in Speed Square at the Gold Saucer until you complete the Whirlwind Maze on Disc 2
Shotgun, Four Slots & Mythril Clip: Sold at the shop in Rocket Town, Costa del sol and Junon until you complete Whirlwind Maze on Disc 2
Javelin: Found in Gaea's Cliff
Trine: Enemy Skill in Gaea's Cliff
Earth Mallet: Drops from Gigas, an enemy in the Whirlwind Maze on Disc 2
Neo Bahamut Materia: Found in Whirlwind Maze on Disc 2
MP Turbo Materia: Found in Whirlwind Maze on Disc 2 (Same screen as Jenova-Death)
Poison Ring: Found in Whirlwind Maze on Disc 2 (Same screen as Jenova-Death)
Trine: Godo in the Wutai Pagoda Side Quest is your last chance of learning this ability, make sure Yuffie is equipped with all Enemy Skill Materia that don't know this ability
Elemental Materia #3: On Disc 2 while Tifa is lead of your party examine the piano in Nibelheim for this Materia. This only works if you told your party that you "jammed on it" in the Nibelheim Flashback.
Ultima Materia: When saving North Corel from the speeding train during the Disc 2 Huge Materia Quest, if you do not at least board the train you won't be able to get Ultima
Warrior Bangle: Steal from Eagle Gun, a boss that's only found on the speeding train during the North Corel Huge Materia Quest on Disc 2
Corel Huge Materia: You have to stop the train during the Disc 2 Corel Huge Materia Quest to receive this Key Item
Imperial Guard (#1): Fight the CMD Grand Horn enemy at mandatory Fort Condor battle during Disc 2
Fort Condor Huge Materia: If you lose to the CMD Grand Horn in Fort Condor you'll lose your chance of getting this Materia forever
Curse Ring (#1): Obtained by completing the Beat Up Key Side Quest in Mideel while Cid or Tifa is the leader of your party on Disc 2
Curse Ring (#2): Steal from Ultimate Weapon when he attacks you in Mideel
Battle Trumpet: Found in the Underwater Reactor during Disc 2 after defeating the boss of the dungeon but before leaving
Scimitar: Found in the Underwater Reactor during Disc 2 after defeating the boss of the dungeon but before leaving
Leviathan Scales: Found in the Underwater Reactor during Disc 2 after defeating the boss of the dungeon but before leaving. This item is used in extinguishing the fires in the Da Chao Fire Cavern
Underwater Huge Materia: If you fail the Submarine battle mini game you won't be able to obtain this Huge Materia
Ziedrich (#1): Steal from Rude on the Sunken Gelnika during Disc 2
Touph Ring (#1): Steal from Reno when you fight him on the Sunken Gelnika during Disc 2
Ziedrich (#2): Steal from Rude in Rocket Town when you face off against him
Rocket Town Huge Materia: Open the Rocket Ship's container to obtain this Huge Materia
Rising Sun: Stolen from Diamond Weapon when it attacks Midgar during Disc 2
MP Absorb Materia (#1): Found during the Wutai Side Quest, if you don't complete it before your return visit to Midgar on Disc 2 you'll no longer be able to obtain this
HP Absorb Materia (#1): Found during the Wutai Side Quest, if you don't complete it before your return visit to Midgar on Disc 2 you'll no longer be able to obtain this
Aegis Armlet: Found at the first part of the Return to Midgar during Disc 2 (If you go across the platform that collapses before grabbing this you'll miss this forever)
Starlight Phone: Found during the Return to Midgar raid on Disc 2
Max Ray: Found during the Return to Midgar raid on Disc 2
Ziedrich (#3): During your fight with the Turks during the Return to Midgar raid on Disc 2, steal this item from Rude
Touph Ring (#2): During your fight with the Turks during the Return to Midgar raid on Disc 2, steal this item from Reno
Minerva Band (#2): During your fight with the Turks during the Return to Midgar raid on Disc 2, steal this item from Elena
Graviball: Steal from the Shadow Maker enemy in the Midgar tunnels during the Return to Midgar raid on Disc 2, this is your last opportunity to get this item
Behemoth Horn: Found in the Shinra Building during the Return to Midgar raid on Disc 2
Grow Lance: Found in the Shinra Building during the Return to Midgar raid on Disc 2
HP Shout: Found in the Shinra Building during the Return to Midgar raid on Disc 2. This is Cait Sith's Ultimate Weapon
Pile Bunker: Found in the Shinra Building during the Return to Midgar raid on Disc 2
Master Fist: Found in the Shinra Building during the Return to Midgar raid on Disc 2
Turtle's Paradise Newsletter No 2: Found on the second floor of the Shinra Building during the Return to Midgar raid on Disc 2. This is your last chance of reading this flyer, if you don't do it now you will never be able to complete the side quest.
Mystile (#1): Found during the Return to Midgar raid on Disc 2
8inch Cannon: Dropped and stolen from many different enemies that you encounter during the Return to Midgar raid on Disc 2
Shinra Alpha: Stolen from SOLDIER:1st during the Return to Midgar Raid on Disc 2
Missing Score: While climbing the stairs to fight Hojo during the Return to Midgar Raid on Disc 2 you'll find Missing Score, Barret's Ultimate Weapon. Barret must be in your party for you to obtain this weapon - this is also your only chance of getting the weapon... You can never return to this same location
L5 Death: You can never learn the L5 Death Enemy Skill if all of your characters are higher than level 95
L4 Suicide: You can never learn the L4 Suicide Enemy Skill if all of your characters are higher than level 96
Mystile (#3): Acquired by doing the duplication bug in Northern Crater
Shield Materia (#2): Acquired by doing the duplication bug in Northern Crater
Imperial Guard (#3): Acquired by doing the duplication bug in Northern Crater
Pandora's Box: You can never learn the Pandora's Box Enemy Skill if you miss it the first time it's used. It's only used a single time per save file