Buncha youngins with your GBAs.

My favourite OG gameboy game was Kirby's Dream Land. Played and replayed it many times. Even had one of those attachments to magnify it and light up the screen when it got dark :)

• Metroid II is one of my favorite games of all time.
• Mega Man: Dr. Wily's Revenge and Operation C are both highly polished and fun, but quite challenging.
• Teenage Mutant Ninja Turtles: Fall of the Foot Clan is a relatively easy, short, polished action game.
• Kirby's Dream Land is my favorite game in the series. And if you think it's too easy, turn on Extra Game mode. It will wreck you, I promise. ;)
• Ninja Gaiden Shadow and Castlevania II: Belmont's Revenge are amazingly polished challenging but fair action games.

Every game I mentioned has excellent music, is an original game (not a port), and I have played in their entirety again and again throughout the years.

Let me know if you're looking for a genre other than an action game. XD

Kingdom Hearts: Chain of Memories. Has to be one of the best GBA games made

If we're allowed GBA then Zelda Minish Cap or Lego Star Wars.

I really enjoyed Kirby and the Amazing Mirror

I will never not shill advance wars 1 and 2 Great gameplay, great artstyle, great everyting

Advance Wars.

The Megaman Battle Network series on GBA is awesome. Replayed a few of them last year and they are still great.

I know you mentioned Zelda, but there were actually a ton of pretty good Zelda games like Oracle of Ages/Seasons. Advance Wars was pretty fun. Golden Sun too. I also have to agree with MMBN from the other commenters.

Advance Wars for GBA was up there for me (below any Zelda game). I've got my eyes on the Switch remake, but holding until I can find it on sale.

Never sleep on Wario land

Golden Sun GBA. GBC, Wacky Racers and GB it was Tetris because I had nothing else, lol.

Fire Emblem 7 a.k.a The Blazing Sword

Pocket Bomberman (GBC), Wario Land (GB), Wario Land II (GBC), Bubble Bobble Old and New (GBA), Donkey Kong '94 (GB), Kirby's Dream Land and Kirby's Dream Land 2 (GB), Kirby's Nightmare in Dreamland (GBA), Kirby and the Amazing Mirror (GBA), Dr. Mario (GB), Tetris (GB), and Tetris DX (GBC), Mario's Picross (GB).

Wario land, Metroid 2, Donkey Kong 94 are all great

The non-pokemon ones I played the most were:

DMG: Kirby's Dreamland 2

GBC: Shante

GBA: Drilldozer

Platformers to me always felt like the best suited games to handheld games, and I love the bright colorful art styles. Drilldozer is definitely my all time favorite. If you can find a copy, I'd highly recommend it! The rumble pack cartridge is so cool.

Here's a short list of my favorites:

• golden sun
• fire emblem

EDIT: ... I misread the post. Updated to show only Gameboy games. *facepalm

Golden Sun and its sequel, Golden Sun: The Lost Age. Easily my two GBA favourites.

Does Yoshi's Island count? I loved that game to death and it's ending makes me tear up as well.

If you're playing Gameboy specifically, and not including Advanced, then I played a ton of Marble Madness. I never beat it, but it is pretty fun physics-y platformer.

If you are including Advanced, then Metroid Fusion is a classic. Atmospheric, and beautiful sprite work. Genuinely scary in parts, and leads right into Dread if you like the gameplay.

I loved kid Icarus. Played the shit out of the game when I was a kid. That a Kirby's Dreamland were my two favorites that I can recall right now.

I was also going to say MMBN, but since that's been said, I'll say Golden Sun. Loved both of those games to death.

Breath of Fire 1 and 2 are also great (although technically SNES ports).

Harry Potter and The Chamber of Secrets (GBC). I'm convinced it's what got me into JRPGs because of the similarities, despite being a western game. It was localized to my language (Swedish) which was not the case for most games (like pokemon), so young me could actually understand what was going on for once. I really like the art in it too.

So I grew up playing James Bond 007 on my OG Game Boy. It wasn't the greatest game in the world but it provided hours of fun on car trips when I was a kid.

Been playing road rash (GBC) and its nice

Kirby games are nice too

Not exactly my favorite (because we already know Pokémon is) but I do remember playing Tetris a lot. My mom had bought one of the giant grey Gameboys with black & white display in the early 90's and that thing lasted as long as any of the other handhelds we got throughout the years.

The Urbz: Sims in the City for the GBA (and also the DS).
This is such a hidden gem on the GBA and my favorite GBA game I had. Had great music as well!

My favourite GBA game was Metroid Fusion, I wish I still knew where it was

Tetris change my mind