Ms. Pacman: Maze Madness (SLUS-01018)
Correct 16:9 - Note: The game's Widescreen mode is too narrow, use that instead
801F3828 0C00
Eyefinity
801F3828 0400

Colin McRae Rally (SCUS-94474)
Eyefinity
800DCE80 7000
800DCE82 0000

Colin McRae Rally 2.0 (SLUS-01222)
Widescreen
80056BB0 2EEE
80056BB2 0001
Eyefinity
80056BB0 6555
80056BB2 0000

Pacman World (SLUS-00439)
Correct 16:9 - Note: The game's Widescreen mode is too narrow, use that instead
80150FF0 0C00
Eyefinity
80150FF0 0400

Aqua GT (SLES-03390)
Correct 16:9 - Note: The game's Widescreen mode is a bit off to rounding 4:3 math, It's not easily noticable but use that instead.
8012257C 0E5A
Eyefinity
8012257C 04DD

Bloody Roar 2 (SCUS-94424)
Correct 16:9 - Note: The game has 3 Widescreen modes that not even one is correct, use that one instead
801F0018 1333
Eyefinity
801F0018 0666

Driver (SLUS-00842)
16:9 8008AA38 1333
Eyefinity 8008AA38 0666

Driver 2 (SLUS-01161) (Greatest Hits)
16:9 8007F170 0C00
Eyefinity (Not Recommended) 8007F170 0400

Ridge Racer Type 4 (SLUS-00797)
16:9 8006E458 0E00
Eyefinity 8006E458 0800

Saiyuki Journey West [SLUS-01381]
Widescreen mode (16:9)
Cheat
80199174 0C00
Hex code (Thanks to edgbla)
Offset (in SLUS_013.81): 9a084
Old value: 0400E28C
New value: 000C0224

Vanguard Bandits [SLUS-01070]
Widescreen 
80038564 0C00 
80038566 2402

--- update 26.08.15 ---

Aizouban Houshinengi [SLPM-86209]
Widescreen mode (16:9)
801792B0 0C04

Digimon World 3 (SCUS-94488)
Widescreen (battles/3D areas only)
80080B10 0C00
Eyefinity
80080B10 0400

Digimon World 2003 (SLES-03936)
Widescreen (battles)
80081398 0C00
Eyefinity
80081398 0400

Digimon World 2 (SLUS-01193)
Widescreen (messes up your placement on the map on maps with 2D background)
80061A28 0C00

Digimon World (SLUS-01032)
Widescreen for 3D objects (messes up your placement on the map on maps with 2D background)
80136F64 0C00

Ape Escape (SCUS-94423)
Widescreen (16:9)
800AF0A0 0C00
Eyefinity (If you feel adventurous)
800AF0A0 0400

Driver (SLES-01816)
Widescreen
8008A590 1333