Credit goes to Elixirdream and Narin (Me ;p)
These are the codes we hacked already, we are in the process of hacking even more codes for the game including monster and recruitment codes. You can find these codes and many more over at the Massive Cheat Database at
http://cheats.gbatemp.net!!!Dragon Quest V: The Hand of The Heavenly Bride (E)
!!YV5P 9D159278
!!!Dragon Quest V: The Hand of The Heavenly Bride (U)
!!YV5E 49D61323
::Backup Enabler/Game Fix Code
0200819C E3A00000
020081A0 E12FFF1E
!Misc Codes
::Enable Debug Room (Press L)
94000130 FDFF0000
1204191E 000046C0
D2000000 00000000
::Max Gold (Press L+R)
94000130 FCFF0000
0209D7FC 000F423F
D2000000 00000000
::Max Gold Banked (Press L+R)
94000130 FCFF0000
0209D800 0098967F
D2000000 00000000
::Max Casino Tokens (Press L+R)
94000130 FCFF0000
0209D804 0098967F
D2000000 00000000
::Max Mini Medals (Press L+R)
94000130 FCFF0000
0209D808 0098967F
D2000000 00000000
::Equipment Restriction Lifted
02022B64 D00029A1
::Complete Map (Press L+R)
94000130 FCFF0000
C0000000 00000007
020D4488 00000000
DC000000 00000004
D2000000 00000000
::Complete Big Book of Beast (Press L+R)
94000130 FCFF0000
120D424C 000003FF
C0000000 00000005
020D4234 FFFFFFFF
DC000000 00000004
D2000000 00000000
::All Monsters Defeated For Big Book of Beast (Press L+R)
94000130 FCFF0000
C0000000 000000C9
120D3D78 000003E7
DC000000 00000006
D2000000 00000000
::All Item Count For Big Book of Beast (Press L+R)
94000130 FCFF0000
C0000000 000000C9
120D3D7A 000003E7
DC000000 00000006
D2000000 00000000
:Game Time Codes
::Always 000:00
020D443C 00000000
::Always 999:59
020D443C 0CDFD7F0
:Field Codes
::Walkthrough Walls/Objects (Hold Select)
1206A42C 00002001
94000130 FFFB0000
1206A42C 00002000
D0000000 00000000
::Walkthrough Walls/Objects (Hold L)
1206A42C 00002001
94000130 FDFF0000
1206A42C 00002000
D0000000 00000000
:No Random Encounter Codes
::No Random Encounters, Always On
:::Use At Own Risk
12023C70 00002100
::No Encounter v1 (Hold Select to ON)
12023C70 00001C49
94000130 FFFB0000
12023C70 00002100
D0000000 00000000
::No Encounter v2 (R+Up ON,R+Down OFF,R+Right Instant Encounter)
94000130 FEBF0000
12023C70 00002100
D0000000 00000000
94000130 FEDF0000
12023C70 00002110
D0000000 00000000
94000130 FE7F0000
12023C70 00001C49
D0000000 00000000
!Battle Codes
::Critical Hit (Hold L)
0203A918 2002D010
94000130 FDFF0000
0203A918 200146C0
D0000000 00000000
::Always Critical Hit
0203A918 200146C0
::Enemy HP 1/1 / One Hit Kills
:::Use At Own Risk
1200CF6C 00002101
1200CF70 00002101
::Enemy MP Always 0
1200CF74 00002100
1200CF78 00002100
::Enemy Never Attack (L+Up=On, L+Down=Off)
94000130 FDBF0000
12011EC8 000089C0
12011ED2 000089C0
12011EDC 000089C0
12011EE6 000089C0
12011EF0 000089C0
12011EFA 000089C0
D0000000 00000000
94000130 FD7F0000
12011EC8 00002000
12011ED2 00002000
12011EDC 00002000
12011EE6 00002000
12011EF0 00002000
12011EFA 00002000
D0000000 00000000
:Sack Items Codes
:::Use at Own Risk, it includes plot items
::Have All Items x 1 (Press L+R)
94000130 FCFF0000
D5000000 00010001
C0000000 000000FE
D6000000 0209D81C
D4000000 00000001
D2000000 00000000
94000130 FCFF0000
D5000000 00630101
C0000000 00000006
D6000000 0209DC18
D4000000 00000001
D2000000 00000000
::Have All Items x 10 (Press L+R)
94000130 FCFF0000
D5000000 000A0001
C0000000 000000FE
D6000000 0209D81C
D4000000 00000001
D2000000 00000000
94000130 FCFF0000
D5000000 00630101
C0000000 00000006
D6000000 0209DC18
D4000000 00000001
D2000000 00000000
::Have All Items x 99 (Press L+R)
94000130 FCFF0000
D5000000 00630001
C0000000 000000FE
D6000000 0209D81C
D4000000 00000001
D2000000 00000000
94000130 FCFF0000
D5000000 00630101
C0000000 00000006
D6000000 0209DC18
D4000000 00000001
D2000000 00000000
!Character 1 (Hero) Stat Codes
::Refill HP (Press L + R)
94000130 FCFF0000
DA000000 0209DD7E
D7000000 0209DD7C
D2000000 00000000
::Infinite HP
DA000000 0209DD7E
D7000000 0209DD7C
D2000000 00000000
::Max HP
0209DD7C 03E703E7
::Refill MP (Press L + R)
94000130 FCFF0000
DA000000 0209DD82
D7000000 0209DD80
D2000000 00000000
::Infinite MP
DA000000 0209DD82
D7000000 0209DD80
D2000000 00000000
::Max MP
0209DD80 03E703E7
::Max Strength
2209DD78 000000FF
::Max Resilience
2209DD7A 000000FF
::Max Agility
2209DD84 000000FF
::Max Wisdom
2209DD85 000000FF
::Max Luck
2209DD86 000000FF
::Max EXP
0209DD58 05F5E0FF
::Max Level
2209DD63 00000063
!Character 2 Stat Codes
::Refill HP (Press L + R)
94000130 FCFF0000
DA000000 0209E29A
D7000000 0209E298
D2000000 00000000
::Infinite HP
DA000000 0209E29A
D7000000 0209E298
D2000000 00000000
::Max HP
0209E298 03E703E7
::Refill MP (Press L + R)
94000130 FCFF0000
DA000000 0209E29E
D7000000 0209E29C
D2000000 00000000
::Infinite MP
DA000000 0209E29E
D7000000 0209E29C
D2000000 00000000
::Max MP
0209E29C 03E703E7
::Max Strength
2209E294 000000FF
::Max Resilience
2209E296 000000FF
::Max Agility
2209E2A0 000000FF
::Max Wisdom
2209E2A1 000000FF
::Max Luck
2209E2A2 000000FF
::Max EXP
0209E274 05F5E0FF
::Max Level
2209E27F 00000063
:EXP Multiplier Codes
::x2
0200CF94 8981826A
1200CF98 00000049
::x4
0200CF94 8981826A
1200CF98 00000089
::x8
0200CF94 8981826A
1200CF98 000000C9
::x16
0200CF94 8981826A
1200CF98 00000109
::x32
0200CF94 8981826A
1200CF98 00000149
::x64
0200CF94 8981826A
1200CF98 00000189
::x128
0200CF94 8981826A
1200CF98 000001C9
::x256
0200CF94 8981826A
1200CF98 00000209
::x512
0200CF94 8981826A
1200CF98 00000249
:Gold Multiplier Codes
::x2
0200E5E4 47700040
::x4
0200E5E4 47700080
::x8
0200E5E4 477000C0
::x16
0200E5E4 47700100
::x32
0200E5E4 47700140
::x64
0200E5E4 47700180
::x128
0200E5E4 477001C0
::x256
0200E5E4 47700200
::x512
0200E5E4 47700240
:Language Select Codes
::Japanese
2211B7D4 00000000
::English
2211B7D4 00000001
::French
2211B7D4 00000002
::German
2211B7D4 00000003
::Italian
2211B7D4 00000004
::Spanish
2211B7D4 00000005