According to the Nintendo Direct, a first few Game Boy and Game Boy Advance games are now available on the Nintendo Swtich Online. That includes those for certain Nintendo series that you are familiar with. Also, note that there are some that require multiplayer which the Nintendo Switch Online is compatible with. That said, if you have those multiplayer games that both the Wii U and 3DS are not compatible with, you can remove them from the Wii U and 3DS systems. When you do, you’ll have to play them on the Switch online in order to get a true 100% completion on them with the now multiplayer compatibility.
Here is the following Game Boy and Game Boy Advance Games that have multiplayer gimmick that the Switch is compatible with.
- Mario Kart: Super Circuit (GBA)
- Mario & Luigi: Superstar Saga (GBA)
- Super Mario Advance 4: Super Mario Bros. 3 (GBA)
- Super Mario Advance: Super Mario Bros. 2 (GBA) (second wave)
- Super Mario Advance 2: Super Mario World (GBA) (second wave)
- Super Mario Advance 3: Yoshi’s Island (GBA) (second wave)
- Kirby & The Amazing Mirror (GBA) (third wave)
- Fire Emblem (GBA) (third wave)
- Game & Watch Gallery 3 (GBC)
- Pokémon Trading Card Game (GBC) (second wave)
Here is the following games for single player that were temporarily available on the Wii U and 3DS shop and will also be in the Switch online. Believe it or not.
- Super Mario Land 2: 6 Golden Coins (GB)
- Wario Land 3 (GBC)
- The Legend of Zelda: Link’s Awakening DX (GBC)
- The Legend of Zelda: Oracle of Ages
- The Legend of Zelda: Oracle of Seasons
- Kirby’s Dream Land 2 (GB)
- The Legend of Zelda: The Minish Cap (GBA)
- Metroid Fusion (GBA)