[Slydria]

Just a handful of ideas I've had for some Weapon Potentials, no particular rhyme to which ones I thought should have one.

Artemis Replica -
Arrow of Life
Passive: Artemis Replica counts as a valid casting tool for Mercalan spells.
Active: 20FP - Targets an ally (excluding yourself) within your Bow's Attack Range. This restores the target's HP equal to 100% Weapon ATK + 80% Light ATK. 1 Round Cooldown.

Braver Replica -
Golden Spirit
When you are at or under 50% of your Maximum HP, you gain the effects of Golden Glow (LV = UL/2%) and Golden Blade. (On Hit: Deal bonus unresistable Light Damage equal to UL+1.)

Gae Bolg Replica -
Heartseeker - 20FP
Targets an enemy within 3 Range, dealing Pierce physical damage equal to 125% Weapon ATK while applying (or worsening) Cursed Wounds equal to the damage dealt, lasting 3 Rounds. This skill can cause critical hits for more damage. 1 Round Cooldown.

Kigal Replica -
Contingency - Huggessoan Spell, 50FP
Grants a status that lasts 3 Rounds: When you would be incapacitated (reduced to 0HP), this status is consumed and instead negates the fatal damage, teleports you to a random location on the battlefield and restores your health equal to 100% Weapon ATK + 200% Dark ATK. Can only be used once per battle.

Nirvana Replica -
Grandstand - 25FP
Grants the user UL+1% Status Resistance for 4 Rounds (or until Knocked Down). Additionally, while this is in effect, whenever you successfully negate an infliction-based status, you attempt to inflict the causer with that same status.

Cobalt Qrytrs -
Rip and Tear
After you land a successful hit, your Critical Chance and Critical Damage are both increased by 10% for 2 Rounds, this benefit stacks up to 3 times.

Screamer -
Relentless Voice
Gain +UL/2 Sound ATK as long as you are not Silenced. Additionally, when you use the Screamer skill, enemies within 3 Range will also take Sound magic damage equal to 100% Weapon ATK and 100% Sound ATK.

Citizen Slaughterer, Knight Slayer, Rogue Dasher -
Vex Armor
Targets an enemy within 4 Range, for 3 Rounds, they will be treated as having Unarmored armor (if using Citizen Slaughterer), Light Armor (if using Rogue Dasher) or Heavy Armor (if using Knight Slayer). Any passive abilities of the target dependent on Armor Type will be impacted for this duration. 5 Round Cooldown.

Tier 3 Elemental Tomes (Ampgeneoule, Blackmeteor, Chorusafhybyn, etc.) -
Element Malediction - 20FP
Afflicts an enemy with an elemental curse. Targets an enemy within 4 Range and applies Elemental Weakness (LV 30) to this Weapon's Damage Type for 3 Rounds. (Elemental Weakness effects don't stack, only the strongest applies.)

Magical Weapons (Magical Moon, Magical Star, Magical Sun, etc.) -
Astral Power
Reduces the FP Cost of spells that match your Starsign by UL+1%. (For instance, Mars Starsign reduces the cost of Nerhaven spells. This reduction does not stack with Efficiency subtalent.)

Additionally, after casting a spell of the appropriate type, your Weapon is empowered, causing the next successful basic attack to deal additional armor-ignoring magical damage equal to 100% Elemental ATK.

Crystal Blade -
Crystal Shell - 20FP
Creates a Crystal Shell around the user for 4 Rounds, granting (UL/2)+3 bonus Armor and Magic Armor. Additionally, you will retaliate any attackers within 4 Range of you, dealing unresistable Earth damage equal to twice the Armor Bonus and causing Crystalize on them for 2 Rounds.

Bandit Weapons (Bandit Sword, Highwayman Axe, Hold-Upper, etc.) -
Cutpurse
This weapon deals bonus damage (divided by Rounds) equal to the Flanking bonus you would receive and grants the user access to the Pilfer Skill. (Pilfer targets an enemy within 1 Range with a chance equal to 50% + Scaled GUI + Thievery Bonuses to prevent them from using items for 4 Rounds.)

Spirit Weapons (Siphon, Spirit Axe, Spirit Sword, etc.) -
Hyper Focus
Imbues the user's weapon with intense focus, increasing this Weapon's effective Power, Accuracy and Critical Chance by UL but you also are inflicted with Worn Out (LV = UL/2) and do not gain Focus from this weapon's passive effect. This lasts indefinitely, instead the effects end if you run out of FP or can be ended early by reusing this Skill while in effect.

[PantherPrincess]

These are pretty solid and interesting. +1 from me.

[Fern]

10/10.

I have nothing bad to say about this list.

[Lolzytripd]

Cobalt Qrytrs -
Rip and Tear
After you land a successful hit, your Critical Chance and Critical Damage are both increased by 10% for 2 Rounds, this benefit stacks up to 3 times.

Sure you don't mean Creed replica?