World Select - Obelix (E) (SGB)

System: (Super) Game Boy
Game Title: Obelix (E) (M2) (Eng-Spa) [S][!]

World Select (Options Menu)
At the Title Screen press Left, Left, Left, Left, Right, Up, Up, Down, Select, Right, Right.

Game Genie code:
World Select Unlocked (Options Menu)
0CA-14A-806

Cheats - The Lost World: Jurassic Park (U) (SGB)

System: (Super) Game Boy
Game Title: The Lost World: Jurassic Park (U) [S]

Infinite Health
At the Title Screen press Left, A, Up, Right, A, Down, you will  hear a confirmation sound.

Infinite Ammo
At the Title Screen press Select, Up, Up, Select, Down, Down, you will  hear a confirmation sound.

Stage Select Replaces Password Menu
At the Title Screen press Up, Down, B, B, A, you will  hear a confirmation sound.

Game Genie Codes

Infinite Health (LAURAD)

287-6EF-6EA

Infinite Ammo (Se UU Se DD)

285-D9B-6EA

Stage Select Replaces Password Menu (UDBBA)

3CE-22A-3B4

Stage Skip - Little Indian in Big City (U) (SGB)

System: (Super) Game Boy
Game Title: Little Indian in Big City (U) [S]
A.K.A. Un Indien Dans La Ville

Stage Skip - Little Indian in Big City (U) (GB)

Stage Skip:
Pause the game and press Right 4 times, Down 3 times, Left 2 times, and Up once.
You will hear an annoying sound if done correctly, press Select to skip to the next stage.

Game Genie Codes:
Stage Skip Enabled
182-0F9-6E9
042-109-19D

Note: Pause the game and press Select to skip to the next stage.

Nintendo Super Game Boy

System: Super Game Boy
Game Title: Super Game Boy

I've put together a graphical list of enhanced English Game Boy games when played on a SNES.
This does not include Game Boy Color.

http://nintendosupergameboy.blogspot.com/

View Endings - Battle Arena Toshinden (U) (SGB)

System: (Super) Game Boy
Game Title: Battle Arena Toshinden (U)

View Character Endings
At the Takara logo press:
B, Select, A, Select, Right, Left, Down, Up.

Unknown Cheat
At the Title Screen press:
Up, Down, Left, Right, Select, A, Select, B

Cheat Mode - Hunchback of Notre Dame (U) (SGB)

System: (Super) Game Boy
Game Title: Hunchback of Notre Dame (U)

Cheat Mode Password:
PSCGM
Press A to increase the number of balls, and Select to beat the stage and move to the next.

Passwords:
00000
04419
75939
95567
76431
75407
55762
41403
59269
38793
44722
76792
54146
13258
10017
59657
41389
41858
19566
83203
25112
58415
34693
24872
41984
75478
30434
68066
67782
83840
39074
11320

Chiseler Stage Passwords
01 CNRPQ
CKKCT
PLTHT
SLMNP
PNKHD
PLJBQ
LMPNF
KDKBH
MTGNT
10 JSQTH
JJPFF
QNPSG
LKDKM
DHFMQ
CBCDP
LSMLP
JCHRS
KFRMR
CTMMP
20 RJFCH
GMCDG
LSJCL
HKNSH
FKSQG
KDTRJ
PMKPR
HCJHJ
NQBPM
MPPRG
30 RJRKC
JTCPK
FDHFB
GCCND
MJDHR
BJNNT
NSSHT
DLJMB
KKFTT
BKPSF
40 KMSMM
MSSBG
SNMGB
BTNRG
TSLRG
BFJJN
JLNSQ
GNCFC
RQTBL
TJLBD
50 JJSKS
MNJLP
QQNCN
GPSCM
SLBDJ
NFPTM
KPSDC
HMLMJ
JJFQL
PNSHR
60 QQSFT
PPQJC
QFLMQ
TKDPM
HCLRM
FFGSR
CMKDG
TSLKS
SRRGM
SMFNM
70 FPFMG
LPSPQ
QHMKS
LDNCQ
DKLLF
NRRRH
LHCQL
CGQGH
TCKKG
SSLJG
80 RNHQT
SSHML
CPRTL
PLRBB
CFCCH
KPHFP
DPKFL
GCLTD
CCSQH
DJJLR
90 CNTGD
NMKKD
NSJSD
PGJND
KBNQP
SSNQP
QHSCN
CBQLL
CPTMF
NFGCL
100 JHHRM

Stage Select - Iron Man & X-O Manowar in Heavy Metal (U) (SGB)

System: (Super) Game Boy
Game Title: Iron Man & X-O Manowar in Heavy Metal (U)

Developer Level Select Menu
Password: LSLSDB
Pause the game, hold either up or down and unpause.

Stage Passwords:
01 TYCKPQ
02 TJYPDF
03 ZXCVBM
04 KDZCPL
05 MHGQZS
06 SPLHRJ
07 YPMBCK
08 SDWZCM
09 DPWMQZ
10 LKLPDX
11 XCSQSS
12 MPQPRY
13 JKRTSC
14 DXCMGH
15 LPJKHX
16 XCSMMN
17 VNTMZS
18 SXZPLK
19 MPKHKG
20 BMQZHL

Game Genie code:
Developer Level Select Menu
081-BDF-4C1

Note:
Pause the game, hold either up or down and unpause.

Test Mode - World Heroes 2 Jet (U) (SGB)

System: (Super) Game Boy
Game Title: World Heroes 2 Jet (U)

Game Genie Codes:

Infinite Health Player 1

C9A-10F-E62

Boot Into Test Mode
0B0-D9E-E6A

Test Mode:
On the Takara screen, quickly press:
Up, B, A, Down, B, A, Left, Right


Also, here is another unknown cheat.
I don't know how to access it.

40 u
80 d
20 l
10 r
04 se
01 a
04 se
02 b
01 a

up 40
down 80
left 20
right 10
a 01
b 02
select 04
start 08