Here are the Game Boy and Color games I would recommend getting. There's a lot of platformers in these consoles!
- Super Mario Land 2: 6 Golden Coins
- Wario Land: Super Mario Land 3
- Wario Land II
- Wario Land 3
- Pok?mon Red/Blue/Yellow
- Pok?mon Green (Japan-only)
- Pok?mon Gold/Silver/Crystal
- Kaeru no Tame ni Kane wa Naru (For the Frog the Bell Tolls)
- The Legend of Zelda: Link's Awakening
- Shantae
- Donkey Kong '94
- Gargoyle's Quest
- Kirby's Dream Land
- Kirby's Dream Land 2
- Mole Mania
- Mario's Picross
- Metal Gear Soild
- Metroid II: Return of Samus
- The Legend of Zelda: Oracle of Ages & Seasons
- Mega Man V
- Donkey Land, 2 and III
- Kwirk
- Super Mario Land (warning: extremely short game)
- Mario Tennis
- Kirby's Tilt 'n' Tumble
- Dragon Warrior I & II
- Dragon Warrior III
- Bionic Commando
- Castlevania II: Belmont's Revenge
- Contra: The Alien Wars
- F-1 Race
- Final Fantasy Adventure (Seiken Densetsu 1)
- Final Fantasy Legend 2
- Kid Dracula
- Kid Icarus: Of Myths and Monsters
- Super R.C. Pro-Am
- Trip World
- Kirby's Block Ball
- Tetris
- Ninja Gaiden Shadow
- Super Mario Bros. Deluxe
- Toki Tori
- The Battle of Olympus (Japan-only)
- Chalvo 55 (Japan-only)
- X (Japan-only)
This list has pretty much every game that I consider worth playing, although it's not every Game Boy game in existence. Keep in mind that some of these games are also available on 3DS VC.