An as-complete-as-possible list of the special/rare effects that can be found on accessories.
Introduction
I’ll not consider as special the effects that some types of accessories have as their fixed one, like “Enemy Detection” and “Luck”. Except, of course, for the fixed effect of the unique “Peculiar Inner Elixir” accessory.
P.S. In case you’re wondering: it’s absolutely possible to find accessories with 3 special effects on them: a grey one, a purple one and a light-green one. It’s also possible to find accessories with both “Equipment Drop Rate” and “Drop Rate”, and probably with “Luck” too.
The list
Grey effects: - Dragon's Cure Pot Max. Uses +1 - Ammo Held Max +1 - Equipment Drop Rate so far, found with B+ (4★) and A-/A (5★) - Drop Rate so far, found with A- (5★) - Marking Flag Detection - Defense + so far, found with +14/+15 (5★) - Attack Power + so far, found with +14 (5★) Notable mentions: I have one 5★ accessory with "Flame Attack Power +20" while all the other "<Element> Attack Power +" effects on other 5★ accessories never went past +19. So, +20 exists but must be super rare. I also found a 5★ accessory with "Luck +30" instead of +29, so yeah, super-rarely the values can be a tiny bit higher. Red effects: I haven't found any special red effect on accessories yet. Unless "Damage Dealt +2.4%" is special, but I doubt it. Dark-green effects: Same here, I haven't found any special ones. Blue effects: Same here. Purple effects: - Power Gain upon HP Recovery - Power Gain upon Deflection - Damage Reduction upon HP Recovery - Damage Reduction upon Deflection - Spirit Fervor upon HP Recovery - Spirit Fervor upon Deflection - Haste upon HP Recovery - Haste upon Deflection - Ammo Retrieval upon Ranged Attack so far, found with 6.0% (5★) Light-green effects: - HP Restoration from Wizardry Spell Damage so far, found with A- (5★) and A (on the unique "Peculiar Inner Elixir") - HP Restoration from Melee Attack Damage so far, found with A- (5★) - HP Recovery upon Deflection so far, found with +4 (5★)