Still trying to actively beat all the songs on the highest difficulty in Taiko no Tatsujin and the DLC+ mod. Feel like I might break my 3DS in the process, but oh well, why do I own three of the things if not to use them? I can only play the game for an hour, maybe two a day before my fingers cramp up and I loose focus though, so it is kind of self-limiting.
Mario Kart 7 CTGP-7 still goes hard and I frequently play the odd online match against friends or randoms. I also spend 15 - 30 minutes a day playing the Mii Plaza games thanks to netpass.
Occasionally I boot up the pokemon main series games (OR/AS, US/UM, X/Y) and waste some time trying to beat my spree in the battle tree / tower / mansion / whatever, that always sucks me in for a few days at a time at least.
Kirby Triple Deluxe I'm still trying to 100%, and it gets played for a few hours here and there. I probably have several dozen other games in my backlog I'm going to get to eventually, but there's no rush. Titles I never picked up on release, etc. I want to play through Xenoblade Chronicles on the 3DS before I play through the sequel on switch, for example.
While the 3DS is "officially" dead, it is still very much alive in my heart, and the people who keep the games and community alive, such as the folks over at CTGP-7 and netpass, deserve a
huge shoutout

!