Kingdom Hearts/Kingdom Hearts Final Mix Synthesizing and Postards Guide

Most data from http://kingdomhearts.wikia.com/wiki/Postcard

Postcards: 


Before Guard Armor fight

1. Lock on to and then hit the fan in the Item Shop.
2. On the roof top of Cid's accessory shop, reachable via High Jump and Glide, or some careful crate placement.
3. The chest on the right hand side when entering the Second District from the first. It will be on an awning and can be reached by standing on the corner lamp post.

After Guard Armor fight

1. In the chest in the First District after using the Blue Trinity near the Item Shop.
2. In the blue safe in the First District (next to where Cid stands after he opens the Gummi shop).

During Second Episode in Traverse Town:

1. Use the Thunder spell on the exposed wires in the Third District then go to the Gizmo Shop and press down the three buttons on the second floor, utilizing the newly activated lifts, then examine the clock on the first floor of the gizmo shop twice and receive two postcards.
2. Climb the ladder to the side of Gizmo Shop and jump across the roofs of the houses in the Second District then through the secret opening which leads to where Goofy and Donald first fought the Heartless in the Third District. Use the lock-on on the corner of the balcony.

Obtain Green Trinity:

1. In the Item Synthesis Shop, examine the wall where there are messages.

Clear Monstro:

1. Go to Geppetto's House and look at the small pot on the shelf.

Synthesis:

Blaze Shard	Red Nocturne (6%), White Mushroom (3rd spell - Fire: 100%)
Blaze Stone (Blazing Stone in 1.5 ReMIX) (Final Mix Only)	Chimera (Final Mix Only)
Blaze Gem	Bandit (4%), Fat Bandit (8%), White Mushroom (3rd spell - Fire: 10%/Fire Trio: 40%)
Frost Shard	Blue Rhapsody (12%), White Mushroom (3rd spell - Blizzard: 100%)
Frost Stone (Final Mix Only)	Grand Ghost (Final Mix Only)
Frost Gem	Sea Neon (4%), Sheltering Zone (8%), White Mushroom (3rd spell - Blizzard: 10%/Blizzard Trio: 40%)
Thunder Shard	Yellow Opera (8%), White Mushroom (3rd spell - Thunder: 100%)
Thunder Stone (Lightning Stone in 1.5 ReMIX) (Final Mix Only)	Black Ballade (Final Mix Only)
Thunder Gem	Aquatank (8%), Screwdiver (4%), White Mushroom (3rd spell - Thunder: 10%/Thunder Trio: 40%)
Lucid Shard	Shadow (6%), White Mushroom (3rd spell - Gravity: 100%) Gigant Shadow (Final Mix Only)
Lucid Gem	Gargoyle (4%), Wight Knight (4%), White Mushroom (3rd spell - Gravity: 10%/Gravity Trio: 40%)
Lucid Crystal	Darkball (1%)
Power Shard	Bouncywild (Banana peel - 24%/Defeated - 12%), Powerwild (Banana peel - 16%/Defeated - 8%), White Mushroom (3rd spell - Stop: 100%)
Power Stone (Final Mix Only)	Sniperwild (Final Mix Only)
Power Gem	Air Pirate (4%), Battleship (Mast down - 16%/Defeated - 8%) Pirate (4%), White Mushroom (3rd spell - Stop: 10%/Stop Trio: 40%)
Energy Stone (Final Mix Only)	Stealth Soldier (35%) (Final Mix Only)
Power Crystal	Wyvern (2%)
Spirit Shard	Large Body (12%), Soldier (8%), White Mushroom (3rd spell - Aero: 100%)
Spirit Stone (Fury Stone in 1.5 ReMIX) (Final Mix Only)	Gigant Shadow (Final Mix Only)
Spirit Gem	Air Soldier (4%), White Mushroom (3rd spell - Aero: 10%/Aero Trio: 40%)
Bright Shard	Green Requiem (10%), White Mushroom (3rd spell - Cure: 100%)
Bright Gem	Search Ghost (4%), White Mushroom (3rd spell - Cure: 10%/Cure Trio: 40%)
Bright Crystal	Defender (2%)
Shiny Stone (Dazzling Stone in 1.5 ReMIX) (Final Mix Only)	Jet Balloon (Final Mix Only)
Shiny Crystal	Wizard (2%)
Mythril Shard	Barrel Spider (1%), Behemoth (20%), Pot Spider (1%)
Mythril	Angel Star (1%), Behemoth (20%)
Mythril Stone (Final Mix Only)	Pot Scorpion (Final Mix Only)
Mystery Goo	Rare Truffle (Juggle 10 - 10%/Juggles 50 - 40%/Juggle 100 - 100%), White Mushroom (10%/Trio - 20%), Black Fungus (Combo Fin. - 20%)
Mystery Power (Serenity Power 1.5 ReMIX) (Final Mix Only)	Pink Agaricus (Final Mix Only) (40 hits - 10%/70 hits - 20%/100 hits - 100%)
Gale	Angel Star (6%), Invisible (6%)
Gale Stone (Stormy Stone in 1.5 ReMIX) (Final Mix Only)	Neoshadow (Final Mix Only)
Orichalcum	Behemoth (Not Dropped in Final Mix) (20%), Invisible (Not Dropped in Final Mix) (1%) Obtained through chests, and can be purchased in the Item shop for 5000 Munny (Final Mix Only)
Dark Matter (Final Mix Only)	Only obtained through chests, item synthesis, & prizes for mini-games

Tips: 

Behemoth - If you already have the save point of Final Rest, The End of the World, that means you can only find this mob at Hades Cup, and it doesn't drop any item.

Grand Ghost - Use two Elixirs on it and he will be killed.

Chimera - In the Kingdom Hearts 1.5 HD, there is a bug. Holloween Town, Manor Ruins, which you can still see the trinity charge (red trinity) even after you have already used the trinity. If you see the trinity, that means Chimera won't spawn.

Mythril Shard - I have found this video guide: http://www.youtube.com/watch?v=lFpSJq_L7oA And I already tested and did this AFTER Hollow Bastion, so can be used everytime.

Mystery Goo - For easy farm, make this route: 
-Gummi Ship to Deep Jungle, Camp: Tent, go into the camp and farm those mushrooms;
-Go to Camp: Tent and use Gummi Ship to Wonderland, Queen Castle;
-From Queen Castle, go to Lotus Forest and farm the mushrooms;