The following is a list of the best equipment in the game and it's location.

Crossbow (Gastrafitis):
Shop

Ring (Angel Ring):
Shop

Hat (Thief Hat):
Shop

Axe (Slasher):
Shop

Book (Madlemgen)
Poach Great Morbol

Fabric (Ryozan Silk):
Poach Tiamat

Bag (FS Bag)
Poach Wild Boar

Ribbon (Ribbon):
Poach Wild Boar

Cloth (Rubber Conscious):
Poach Hydra

Knive (Zorlin Shape):
Poach a Plague

Stick (Whale Whisker)
Poach Tiamat

Hammer (Scorpion Tail):
Poach Hyundra

Gauntlet (Genji Guantlet):
Steal Elmdor

Mantle (Vanish Mantle):
Gemineas Peak

Perfume (Chantage):
Poach Porky

Harp (Fairy Harp):
4th battle of Deep Dungeon

Rod (Faith Rod):
4th battle of Deep Dungeon

Gun (Blast Gun):
6th battle of Deep Dungeon

Ninja Sword (Kogo Knife):
7th battle of Deep Dungeon

Staff (Sage Staff):
7th battle of Deep Dungeon

Bow (Perseus Bow):
8th battle of Deep Dungeon

Robe (Robe of Lords)
8th battle of Deep Dungeon

Armor (Maximillion):
9th battle of Deep Dungeon

Helmet (Grand Helmet):
9th battle of Deep Dungeon

Knight Sword (Break Blade):
Last battle of Deep Dungeon

Katana (Chirijraden):
Last battle of Deep Dungeon

Shield (Escutcheon II):
Left podium of Nelveska Temple

Spear (Javelin II):
Right podium of Nelveska Temple

Sword (Nagra Rock):
In the back of Nelveska Temple