Table: Accessories (Chrono Trigger) General

Accessory
Used by
Obtain
Effect
Amulet
All
Recruit/Defeat Magus
Prevents all status abnormalities
Aresian Mirror
Ayla, Robo
Arena of the Ages - Win
Counters non-physical attacks 25% of the time
Bandana
All
Crono's Default
Speed +1
Berserker
All
Lab 16 - Chest, Mystic Mountain - Chest
Physical attack and defense up, wearer uncontrollably attacks enemies when time bar is full.
Black Rock
Magus, Marle, Lucca
Kajar - Poyozo in Secret Room
Enables DarkEternal Triple Tech
Blue Rock
Lucca, Magus, Robo
Giant's Claw - Half-hidden Chest
Enables OmegaFlare Triple Tech
Champion's Badge
Frog
Lost Sanctum - Complete the Tower of the Ancients
Masamune critical % increased, Halves MP costs
Charm Top
Ayla
Bangor Dome - Chest in Sealed Room
"Charm" power up
Dash Ring
All
Heckran Cave - Sealed Chest, Ozzie's Fort - Chest
Speed +3
Defender
All
Cathedral - Chest in Magus Room, Robo's Default Accessory
Stamina +2
Dragon's Tear
All
Lost Sanctum - Kill the monsters in the forest
Critical rate increased
Flea Vest
All
Ozzie's Fort - Charm from Flea Plus in the 3-on-3 battle
Magic defense +12
FrenzyBand
All
Giant's Claw - Chest
80% counterattack rate
Gold Erng
All
Arris Dome - Chest in Sealed Room, Black Omen - Charm Synchrite
Max HP +50%
Gold Rock
Frog
Denadoro Mts - After upgrading the Masamune, put Frog in the lead where the Freelancer throws rocks at your party, and let him get hit
Enables Grand Dream Triple Tech
Gold Stud
All
Trann Dome - Chest in Sealed Room, Black Omen - Charm Flyclops
MP use cut by 75%
GreenDream
All
Created by Robo in Fiona's Forest Sidequest
Automatically revives wearer once per battle. The GreenDream remains after use and will continue to work in later battles, but only once in each. HP recovered by the automatic revive is Magic * 5.
Hadean Mirror
Magus
Arena of the Ages - Win
Counters non-shadow attacks 25% of the time
Hero Medal
Frog
Confront Tata after finding the broken Masamune.
Increases Masamune's critical hit rate from 23% to 50%
Hit Ring
All
Arris Dome - Chest in Sealed Room, Black Omen - Charm Giga Mutant (Bottom)
Hit +10
Magic Ring
All
Black Omen - Charm Blob, Death Peak - Chest, Magic Cave - Sealed Chest
Magic +6
MagicScarf
All
Heckran Cave - Chest, Magus's Lair - Chest
Magic +2
Magic Seal
All
Black Omen - Chest
Magic +5, Magic Defense +5
MuscleRing
All
Black Omen - Charm TerraMutant (Top) and Incognito, Sunken Desert - Chest
Stamina +6
Nu Arcana
All
Arena of the Ages - Win
May instantly reduce opponent's HP to 1
Pontic Mirror
Frog, Marle
Arena of the Ages - Win
Counters non-water attacks 25% of the time
PowerGlove
All
Truce Canyon - Chest
Power +2
Power Ring
All
Guardia Forest, 1000 A.D. - Sealed Chest
Power +6
PowerScarf
All
Ayla's Default Accessory
Power +4
Power Seal
All
Black Omen - Charm TerraMutant (Bottom), Black Omen - Chest
Power +5, Stamina +5
PrismSpecs
All
Clear both the Sun Stone sidequest and the Rainbow Shell sidequest and speak to Melchior
Increases all damage the wearer inflicts by 50%
Promethean Mirror
Lucca
Arena of the Ages - Win
Counters non-fire attacks 25% of the time
Rage Band
All
Sewer Access - Chest
50% Counterattack Rate
Relic
All
This accessory was either edited out of the game before release, or never integrated. It can be accessed through a savestate that begins the game with all items, through savestate hacking, or by Game Genie or similar codes.
Shows enemy current/maximum HP, like the SightScope. Does not appear to have any other effect. Has no in-game description.
Ribbon
All
Marle's Default Accessory
Hit +2
SeraphSong
All
This accessory was either edited out of the game before release, or never integrated. It can be accessed through a savestate that begins the game with all items, through savestate hacking, or with Game Genie or similar codes.
Periodically recovers 5 MP during battle
SightScope
All
Lucca's Default Accessory
View enemy's current/max HP, doesn't work on bosses
SilverErng
All
Denadoro Mts - Chest
Max HP +25%
SilverRock
Ayla, Frog, Robo
Laruba Ruins - Get from the Nu that appears late in the game
Enables Spin Strike Triple Tech
SilverStud
All
Denadoro Mts - Chest
MP use cut by 50%
Speed Belt
All
Cathedral - Chest, Magus's Lair - Chest
Speed +2
Sun Shades
All
Complete the Sun Stone sidequest
All damage the wearer inflicts is increased 25%
Third Eye
All
Hunting Range - Nu (Drop), Reptite Lair - Charm Nizbel, Tyrano Lair - Charm Nizbel II
Double Evasion
Uranian Mirror
Crono
Arena of the Ages - Win
Counters non-light attacks 25% of the time
Valor Crest
Ayla
Lost Sanctum (65000000 B.C.) - Defeat the Archaeofangs
Critical rate increased, Counter rate: 50%
Wallet
All
Bangor Dome - Chest in Sealed Room
Get extra money instead of experience points (1:1 exchange rate)
Wall Ring
All
Black Omen - Charm Giga Mutant (Top), Death Peak - Chest, Heckran Cave - Sealed Chest
Magic Defense +10
White Rock
Ayla, Lucca, Marle
Black Omen - Chest
Enables Poyozo Dance Triple Tech

From: Accessories (Chrono Trigger)