I thought I'd seek out some of these games (I had previously only played a few titles on the NES) so I took 5 minutes and consolidated the posts in this thread (so far) so it'd be easier to reference later. It might be useful to one of you.
No particular order. It's interesting to see as a single list.
Excitebike
Metroid
Blaster Master
Super Mario Bros
Super Mario Bros 2
Super Mario Bros 3
Castlevania
Castlevania 2: Simon's Quest
Castlevania 3
MegaMan
MegaMan 2
Bionic Commando
Gradius
Techmo Super Bowl
RBI Baseball
Mike Tyson's Punch Out
Ninja Gaiden
Super Dodge Ball
Legend of Zelda
Zelda II: Adventures of Link
Guantlet 2
Dr. Mario
Tetris
TMNT
TMNT 2
Bases Loaded
MegaMan 2
3D World Runner
Ice Hockey
Double Dragon
Arkanoid
Ballon Fight
GryroMight
Ghosts 'n Goblins
Ultima: Quest of the Avatar
Kirby's Adventure
Metal Gear
A boy and his Blob
RC Pro Am
Micro Machines
River City Ransom
W&W2 Ironsword
Pinball Quest
Rygar
Metal Storm
King's Knight
Super Sprint
Milon's Secret Castlea
Jackal
Skate or Die
Final Fantasy
Who Framed Roger Rabbit
Life Force
Jackal
Golgo 13
Crystalis
Batman
Burger Time
Back To The Future 2 & 3
Jaws
Dragon Warrior 1-4
North and South
Kid Icarus
The flintsones
Duck Hunt
Battle Toads
Contra
Adventure Island 2
Spy hunter
Marble Madness
Duck Tales
Bugs Bunny Birthday Blowout
Super Spike V Ball
Paper Boy
Rad Racer
Kung Fu
Adventures of LOLO
Goonies 2
Top Gun
Mappy
Moon Patrol
Galaga
1942
Battle Chess
Heavy Barrel
Toobin
Bump and Jump
Baseball Stars
Baseball Simulator 2000
Chip & Dale
PacMania
Tetris (Tengen)
Dusty Diamond's All Star Softball
Hoops
NES Football