GBA ?
Its library (especially 1st party) was not that impressive. (Same goes for the DS tbh but that one got a loooot of great games).
I always prioritize quality over quantity. GBA was the home of my all time favorite first party games: Advance Wars, Golden Sun, Fire Emblem (both), WarioWare, Warioland 4 and Mario & Luigi Superstar Saga.
And diversity. GBA had a monster third party support: Sonic, Crash, Spyro, Banjo, Castlevania (x3), Megaman Zero (x4), Boktai, GTA, Max Payne, Kingdom Hearts, Final Fantasy (FFT was one of my favorite GBA games), The Sims, Tony Hawk, Doom, Street Fighter, Tekken, Need For Speed...
Don't get me wrong Switch is one of the greats but in terms of diversity, it's still not up there. Give it time, it's just 3 years old.