Working battlecodes added, some item codes too. Most of these codes are disabled by default, just open the file with notepad and remove the "//" (infront of the patch=1) from the codes you want.
Code:
gametitle=Final Fantasy X [SCES 50490] (E) [A39517AB]
comment=GJohnny
//=========Character Codes=========
//== Tidus ==
//Max HP
patch=1,EE,0031EAC0,short,0000270F
//Max MP
patch=1,EE,0031EAC4,short,000003E7
//Max Sphere Level
patch=1,EE,0031EAD7,byte,000000FF
//Max Stats
//patch=1,EE,0031EACB,byte,000000FF
//patch=1,EE,0031EACC,word,FFFFFFFF
//patch=1,EE,0031EAD0,short,0000FFFF
//patch=1,EE,0031EAD2,byte,000000FF
//All Skills, Specials, WM and BM.
//patch=1,EE,0031EADA,short,0000FFFF
//patch=1,EE,0031EADC,word,FFFFFFFF
//patch=1,EE,0031EAE0,word,FFFFFFFF
//patch=1,EE,0031EAE4,short,0000FFFF
//== Yuna ==
//Max HP
patch=1,EE,0031EB54,short,0000270F
//Max MP
patch=1,EE,0031EB58,short,000003E7
//Max Sphere Level
patch=1,EE,0031EB6B,byte,000000FF
//Max Stats
//patch=1,EE,0031EB5F,byte,000000FF
//patch=1,EE,0031EB60,word,FFFFFFFF
//patch=1,EE,0031EB62,short,0000FFFF
//patch=1,EE,0031EB63,byte,000000FF
//All Skills, Specials, WM and BM.
//patch=1,EE,0031EB6E,short,0000FFFF
//patch=1,EE,0031EB70,word,FFFFFFFF
//patch=1,EE,0031EB74,word,FFFFFFFF
//patch=1,EE,0031EB78,short,0000FFFF
//== Auron ==
//Max HP
patch=1,EE,0031EBE8,short,0000270F
//Max MP
patch=1,EE,0031EBEC,short,000003E7
//Max Sphere Level
patch=1,EE,0031EBFF,byte,000000FF
//Max Stats
//patch=1,EE,0031EBF3,byte,000000FF
//patch=1,EE,0031EBF4,word,FFFFFFFF
//patch=1,EE,0031EBF8,short,0000FFFF
//patch=1,EE,0031EBFA,byte,000000FF
//All Skills, Specials, WM and BM.
//patch=1,EE,0031EC02,short,0000FFFF
//patch=1,EE,0031EC04,word,FFFFFFFF
//patch=1,EE,0031EC08,word,FFFFFFFF
//patch=1,EE,0031EC0A,short,0000FFFF
//== Kimarhi ==
//Max HP
patch=1,EE,0031EC7C,short,0000270F
//Max MP
patch=1,EE,0031EC80,short,000003E7
//Max Sphere Level
patch=1,EE,0031EC93,byte,000000FF
//Max Stats
//patch=1,EE,0031EC87,byte,000000FF
//patch=1,EE,0031EC88,word,FFFFFFFF
//patch=1,EE,0031EC8C,short,0000FFFF
//patch=1,EE,0031EC8E,byte,000000FF
//All Skills, Specials, WM and BM.
//patch=1,EE,0031EC96,short,0000FFFF
//patch=1,EE,0031EC98,word,FFFFFFFF
//patch=1,EE,0031EC9C,word,FFFFFFFF
//patch=1,EE,0031ECA0,short,0000FFFF
//== Wakka ==
//Max HP
patch=1,EE,0031ED10,short,0000270F
//Max MP
patch=1,EE,0031ED14,short,000003E7
//Max Sphere Level
patch=1,EE,0031ED27,byte,000000FF
//Max Stats
//patch=1,EE,0031ED1B,byte,000000FF
//patch=1,EE,0031ED1C,word,FFFFFFFF
//patch=1,EE,0031ED20,short,0000FFFF
//patch=1,EE,0031ED22,byte,000000FF
//All Skills, Specials, WM and BM.
//patch=1,EE,0031ED2A,short,0000FFFF
//patch=1,EE,0031ED2C,word,FFFFFFFF
//patch=1,EE,0031ED30,word,FFFFFFFF
//patch=1,EE,0031ED34,short,0000FFFF
//== Lulu ==
//Max HP
patch=1,EE,0031EDA4,short,0000270F
//Max MP
patch=1,EE,0031EDA8,short,000003E7
//Max Sphere Level
patch=1,EE,0031EDBB,byte,000000FF
//Max Stats
//patch=1,EE,0031EDAF,byte,000000FF
//patch=1,EE,0031EDB0,word,FFFFFFFF
//patch=1,EE,0031EDB4,short,0000FFFF
//patch=1,EE,0031EDB6,byte,000000FF
//All Skills, Specials, WM and BM.
//patch=1,EE,0031EDBE,short,0000FFFF
//patch=1,EE,0031EDC0,word,FFFFFFFF
//patch=1,EE,0031EDC4,word,FFFFFFFF
//patch=1,EE,0031EDC8,short,0000FFFF
//== Rikku ==
//Max HP
patch=1,EE,0031EE38,short,0000270F
//Max MP
patch=1,EE,0031EE3C,short,000003E7
//Max Sphere Level
patch=1,EE,0031EE4F,byte,000000FF
//Max Stats
//patch=1,EE,0031EE43,byte,000000FF
//patch=1,EE,0031EE44,word,FFFFFFFF
//patch=1,EE,0031EE48,short,0000FFFF
//patch=1,EE,0031EE4A,byte,000000FF
//All Skills, Specials, WM and BM.
//patch=1,EE,0031EE52,short,0000FFFF
//patch=1,EE,0031EE54,word,FFFFFFFF
//patch=1,EE,0031EE58,word,FFFFFFFF
//patch=1,EE,0031EE5C,short,0000FFFF
//=========Blitzball Codes=========
//Always Win
//patch=1,EE,0031AB0E,byte,00000063
//patch=1,EE,0031AB71,byte,00000063
//patch=1,EE,0031AB0F,byte,00000000
//Tidus - 5 Tech Slots
patch=1,EE,0031AA4E,byte,00000005
//Tidus - All Tech Abilities
patch=1,EE,003176BC,word,FFFFFFFF
patch=1,EE,003177AC,word,FFFFFFFF
//Tidus - Max Level
//patch=1,EE,0031AA8A,byte,000000FF
//Tidus - Max EXP
//patch=1,EE,0031AC24,short,0000270F
//=========Item Codes=========
//These will put 99 of said item in said slot
//Make sure there's nothing already in the slot
//otherwise it will be gone forever.
//Elixer - Slot 9
patch=1,EE,0031D3AC,short,00002008
patch=1,EE,0031D5A4,byte,00000063
//Megalixer - Slot 10
patch=1,EE,0031D3AE,short,00002009
patch=1,EE,0031D5A5,byte,00000063
//Mega Phoenix - Slot 8
patch=1,EE,0031D3AA,short,00002007
patch=1,EE,0031D5A3,byte,00000063
//Remedy - Slot 4
patch=1,EE,0031D3BA,short,0000200F
patch=1,EE,0031D5AB,byte,00000063
//Master Sphere - Slot 81
patch=1,EE,0031D43C,short,00002050
patch=1,EE,0031D5EC,byte,00000063
//=========Misc Codes=========
//Fully Translated Al-Bhed
patch=1,EE,0031D1E0,word,03FFFFFF
//All Normal Overdrives
//patch=1,EE,0031D23C,word,FFFFFFFF
//patch=1,EE,0031D240,word,FFFFFFFF
//patch=1,EE,0031D244,word,FFFFFFFF
//Have All Key Items
//patch=1,EE,0031D95C,word,FFFFFFFF
//patch=1,EE,0031D960,word,000FFFFB
//patch=1,EE,0031983C,short,00000101
//Inf. Gil
patch=1,EE,0031D218,word,05F5BABE
//No Random Battles
//patch=1,EE,003173F7,word,00000000
//Have all Summons (This may cause instability or weirdness)
//patch=1,EE,201BDAE0,word,26300000
//patch=1,EE,201BDB28,word,2A220012
//DO NOT SAVE WITH THIS CODE ON!!!
EDIT: Updated, fixed battle codes and some item codes added.