Time to mix both GB(C) and GBA platforms with my list:
1. Pokémon LeafGreen (before trying to get any person to fire a nuclear device at me because I haven't said Emerald/Ruby
/Sapphire, know that I wanted my parents to buy me one of these by that time, yet they never wanted)
2. Pokémon Silver (My first video game. Ever.)
3. Donkey Kong Land (GBC)
4. Pokémon Mystery Dungeon: Red Rescue Team
5. Harry Potter and the Philosopher's Stone (How many times I have beaten that game already ? And it's still fun.)
6. Zelda Oracles of Ages/Seasons (I had both cartridges by that time)
7. Wario Land (GB)
8. NES Classics: Metroid
9. Spyro Fusion
I know, there's 9 titles... I hadn't any ideas for a 10th title that was fun enough to me (in my collection) that could take the 10th sport, so I leave it blank.