Angel's Feather - Defeat Alma on Easy/Normal
Lvl. +5

Angel's Coat - Defeat Alma on Easy/Normal
WT 2
ARM 6
RED 15%
Force Dmg Reduction +35%, Fire Resist +50%

Angel's Crystal [Consumable] - Defeat Alma on Hard
All Ability Lvl. +2
Max HP +30
ST+5

Angel's Estoc - Defeat Alma on Hard
WT 2
ATK 11
Crit +10%
Combo +10%

Angel's Boots [ACC] - Defeat Alma on Very Hard
WT 1
Fire Dmg -50%

Angel's Bow - Defeat Alma on Very Hard
WT 3
RAN 13
Range +1
ACC +5%

Zeukrees's Sword - Defeat Zeukrees
WT 7
ATK 30
FOR 10

Zeukrees' Shield - Defeat Zeukrees
WT 7
90%
ARM 25
RED 40%

Lightwing Spear - Defeat Pluton
WT 7
ATK 60
Crit +100%

Shining Arc - Reach the End of the East in Normal mode
WT 4
RAN 43
Range +3, Crit +50%

Edge of the World - Traveled over 3000km in Normal mode and reached the End of the East
WT 15
ATK 40

Dream Sword - Reach the End of the Dream
WT 16
ATK 50
ACC -25%
Combo +200%

For true endings you just have to beat the class unlock quest with the class it unlocks.

Astrology Tome x2 - Complete the Astrologist quest

Oracle Shield - Complete the Astrologist quest as Astrologist
80%
ARM 7
RED 25%
Force RED 30%

Nodachi - Complete the Samurai quest
WT 10
ATK 21
Crit +50%
Combo -40%

Nameless Dagger - Complete the Samurai quest as Samurai
WT 1
ATK 8
Combo +100%

Beast Hunter Quest: Succubus Mist - brainwash whoever comes into contact
Beast Hunter Quest True: Manticore Feather x3 (Floating status for a very short time)

One Way Hero Quest: Demon Lord's Barrier x3
One Way Hero Quest True: Demon Lord's Charm - Call a powerful ally for 2 hours

Dragon Parchment - Complete the Dracon quest

Dragon Spear - Complete the Dracon quest with Draco
WT 5
ATK 12
FOR 10
Crit +20%

Fast-food Chanko (consumable) x2 - Complete the Wrestler quest as Wrestler
HP +60
EN +200

For these you need to reach max affection with the respective ally and win the game (doesn't matter which quest).

Keyton's Sword - Clear the game with Keyton
WT 4
ATK 22
ACC +10%
Crit +40%

Nami's Staff - Clear the game with Nami
WT 2
ATK 10
FOR 12
30% chance to give Max HP and ATK -20% to enemies you attack

Guardian's Shield - Clear the game with Cole
WT 7
80%
ARM 20
RED 40%

Dragonling's Horn [ACC] - Clear the game with Draco
Attack +20%
Force +20%
Force Dmg Reduction +20%

Assassin's Sword - Clear the game with Merril
WT 2
ATK 8
ACC +20%
Crit +100%
Combo +100%

Vow of Purity x3 - Clear the game with Baldur

Aerdou's Spear - Clear the game with Aerdou
WT 9
ATK 20
Crit +15%

Letter From Them [ACC] - Clear the game with Coco & Muddy
WT 1
XP x2

Dosey's Veil [ACC] - Clear the game with Dosey
WT 1
Max HP +25%
Max ST +25%

Storage Manual [Consumable] - Clear the game with Olga
WT+9

Angel's Ribbon [ACC] - Clear the game with Alma
WT 1
Concentrate +1
Max HP +15%