I keep my 3ds games on the upstairs entertainment center shelves to the left of the tv. There are a few DS games in the mix (specifically Harvest Moon and Rune Factory games); but I have them alphabetized. The exception is my Japanese versions of Rune Factory 3 & 4 are next to the English versions so they're all together.
My home console games are in the basement; also on entertainment center shelves. My consoles and the receiver are on the left side. My Switch games are just stacked underneath the receiver, those are also alphabetized too—although there are only a couple of them, and most of the games themselves are in my Switch case, so it's just empty cases on the shelf. My Wii U games are shelved next to the Wii U console since I also didn't have very many of those. Alphabetized. My Wii games are on the right side of the entertainment center; though there's other clutter sharing the shelf with them, and they're done in two rows; one in front, one in back. It's not as alphabetized (it was at some point) but it's more sorted by play frequency with more recently played titles toward the front—or in the case with Super Smash Bros. Brawl, just lying on top of everything else because special.