In 1998 Nintendo released Mini Classic's simulating the vintage Game & Watch's, also adding additional titles.

The games look like small little individual gameboys on a keychain:

They were sold and packaged in blisterpacks:

Titles released under Mini Classic's include:

Fire

Zelda

Octopus

Oil Panic

Parachute

Donkey Kong

Snoopy Tennis

Donkey Kong Jr.

Super Mario Bros.

Mario's Cement Factory