Dash Galaxy in the Alien Asylum (NES 1990) Game Genie Codes

SZVPTOVK - Don't lose lives in rooms
SZUPLOVK - Don't lose lives in elevator shaft
PENPIALA - Start with 1 life
TENPIALA - Start with 6 lives
PENPIALE - Start with 9 lives
NYSXAOAN - Oxygen used up more slowly in shaft
AYXXSNNY - Oxygen used up more quickly in rooms
AAEPZIPA - Don't take damage from shots and collisions
VTNSEXSX - Infinite bombs in elevator shaft
VVVSXXSX - Infinite bombs in rooms
VVOSSXSX - Infinite detonators in shafts
VTESNUSX - Infinite detonators in rooms
VTEZIKSX - Infinite keys in shafts
VVOXTOSX - Infinite keys in rooms

And some Game Genie level select codes:
OZEPOISE + IAEPXSVI - Start on level 5
OZEPOISE + ZAEPXSVS - Start on level 10
OZEPOISE + YAEPXSVS - Start on level 15
OZEPOISE + GPEPXSVI - Start on level 20

The Legend of Zelda (NES 1987) Game Genie Codes

NYKPOYZX - Create character with 16 life hearts
SZNZVOVK - Infinite bombs
OSKUILTA - Wear a red ring
AVVLAUSZ - Don't take damage from anything
YYKPOYZZ - Create character with 8 life hearts
SZVXASVK - Don't lose rubies when buying
ESKUILTA - Wear a blue ring
SZVXASVK +
AEVEVALG - All items for free