"FILE A" codes affect only the game stored in FILE A.

DFDF-FAAD Start FILE A game with 2 lives
DBDF-FAAD Start FILE A game with 10 lives
7FDF-FAAD Start FILE A game with 50 lives
17DF-FAAD Start FILE A game with 100 lives
C2C1-D4AA Infinite lives
6D84-DF03 Infinite time
C26B-0FBF 1-up worth nothing
D5DF-FADD Allows you to select any world for FILE A
CB81-0D02 + E281-0D62 + 3C81-0DA2 Jump lower--Switch off effects if you get stuck
CB81-0D02 + EC81-0D62 + 3C81-0DA2 Super jump
CB81-0D02 + E681-0D62 + 3C81-0DA2 Mega-jump
D62F-6DAE Invincibility does not last as long
9D2F-6DAE Invincibility lasts longer

The Lost Levels

DFDF-FEDD Start FILE A game with 2 lives
DBDF-FEDD Start FILE A game with 10 lives
7FDF-FEDD Start FILE A game with 50 lives
17DF-FEDD Start FILE A game with 100 lives
C2B6-A455 Infinite lives
6D82-0F79 Infinite time
DADF-F30D + D7DF-F36D Allows you to select any world or level for FILE A

Super Mario Bros. 2h

DF61-05D0 1 life after continue
DB61-05D0 9 lives after continue
7461-05D0 50 lives after continue
1761-05D0 99 lives after continue
C26E-D5A6 Infinite lives
DF6B-A9A1 Continue with 3 hearts instead of 2
D46B-A9A1 Continue with 4 hearts
DD32-6966 Never lose hearts
7A60-A966 Jumping in place charges super jump
D1D4-FA0D Allows you to select any world for FILE A

Super Mario Bros. 3

DDAF-A8A3 Fly at any time (run meter always full)
EEA4-AB63 You can fly for as long as you want, until you land
E1A3-D60A Start and continue as Big Mario
CB69-AC07 + DF69-AC67 Change to Big Mario whenever you go to the map
CB69-AC07 + D469-AC67 Change to Fire Mario whenever you go to the map
CB69-AC07 + D769-AC67 Change to Raccoon Mario whenever you go to the map
CB69-AC07 + D069-AC67 Change to Frog Mario whenever you go to the map
CB69-AC07 + D969-AC67 Change to Tanooki Mario whenever you go to the map
CB69-AC07 + D169-AC67 Change to Sledgehammer Mario when you go to the map
1D0A1-6C0A + E1A3-D60A All power-ups turn you into Shoe Mario--May cause 
some graphics to mess up

With the collision codes, you stil lose a life from the
collision, then you're invincible except from falls

D4A8-6CAA Collisions turn you into Big Mario
D7A8-6CAA Collisions turn you into Fire Mario
D0A8-6CAA Collisions turn you into Raccoon Mario--can make him get 
"tangled" in collisions--turn off effects to get loose
D9A8-6CAA Collisions turn you into Frog Mario
D1A8-6CAA Collisions turn you into Tanooki Mario
D5A8-6CAA Collisions turn you into Sledgehammer Mario
C23B-680D After getting a star, invincible until end of level--May have to turn off
effects to jump up
DFBB-DBAF 1 life after continue
DBBB-DBAF 10 lives after continue
FBBB-DBAF 26 lives after continue
74BB-DBAF 51 lives after continue
17BB-DBAF 100 lives after continue
82BB-0C6D Infinite lives
D93E-6C49 Gain lots of lives with each 5 coins (up to 99 lives)

For the next four codes, you must first get atleast 100 coins

D93E-6819 You only need 5 coins for a free extra life
DC3E-6819 You only need 10 coins for a free extra life
FB3E-6819 You only need 25 coins for a free extra life
743E-6819 You only need 50 coins for a free extra life
AD3E-6801 Power jump
863E-6801 Super jump
8D3E-6801 Mega-jump
C63E-6801 Ultra power jump
DDA9-A603 Skywalking (stay up until you release the jump button)
6D3D-6619 Infinite time
D5D4-F36D Select any world for FILE A game--Doesn't work on World 8