Chapter 0
Sealed Box - Send.
Jewelled Blade Grimrist - Keep.

Chapter 1
Crown of Felmar - Send.
Secret of Damascus - Send.
Emerald Necklace - KEEP!

Chapter 2
Holy Grail - KEEP!
Faim Fenn - Send.
Tiara of the Holy Empress - Send.
Bark of the Dryad - Keep.
Inscribed Fragment - Send.

Chapter 3
Golden Fowl - KEEP!
Grand Sting - Send.
Mirage Robe - Keep.
Mirror of Pleiades - Keep.

Chapter 4
Manual of Resurrection - KEEP!!! Once you get the Creation Gem from Lezard's Tower later, you can transmute this thing into Orihalcon and then the Creation Jewel, which'll let you transmute some REALLY kickass stuff from items you'll find along the way.
Holy Sword "Seraphy" - Send.
Spear "Basilisk" - Keep.
Bracelet of Zoe - Keep. Keep. KEEP.
Coin of Fortune: KEEP!

Chapter 5
Holy Wand "Adventia" - Send.
Robe of Bryttain - Keep.
Star Guard - Keep.
Eternal Lamp - KEEP!
Holy Water of Mithra - Keep. Very handy on some upcoming bosses, as it does 100,000 damage to undead.

Chapter 6
Rust-red Circlet - Send.
Dragoon Tyrant - Send.
Reflect Armor - Keep.
Slashing Sword "Farewell" - Send.
Tear of the Cosmos - Keep. It transmutes into another Holy Water of Mithra.

Chapter 7
Accursed Flame Gem - Send.
Elven Bow - Keep, it's a great bow for Lenneth. Note: you have to leave the Forest after getting the Gem and go back in to find a new boss and afterwards get this and the next artifact.
Arectaris - Send.
Ambrosia - KEEP. It permanently adds 6,000 to one character's max DME.
Ruby Music Box - Send.
Bracelet of Basilisk - Keep.
Richebourg - Send.
Mask of the Dead King - Keep.

Chapter 8
Scroll of Golem - Send.
Hourglass of the Gods - Send.
Dragoon Faith - Keep.
Shadzard - Send.
Secrets of Zolon - Send.
Unicorn's Horn - Keep. Also be sure to find the Wand of Apocalypse in this dungeon(Arianrod Labyrinth), as it allows Great Magic without breaking, and is even more powerful than the Unicorn's Horn.
Armor of Aleph - Keep.
Harp of Atrasia - Send.
Berserker Bow - Send.