Since you have pretendo ready, try playing some smash bros or mariokart 7. also instal h shop for more games, its very limited sadly

spotpass is sadly dead but i use swapdoodle to keep a mini diary. You can also download music to ur SD and have no-ad playlists on 3DS sound!

You have access to 3DS, DS GBA VC (inject, don't emulate), SNES, NES, GB/C. When I modded my 3DS many years ago I went to a games rating site like metacritic. Metacritic lets you look at all rating from best to worst per specific console. Try any game that sticks out to you :)