Here’s a fork of Citra that can connect to the official nintendo network, still avilable now, by the person who made CTGP7 (custom tracks and characters in MarioKart 7), and here’s the one for Yuzu. I think these are gonna be the main forks because they already have quite a lot of activity. It’s cool that Citra and Yuzu were open-source so things like this can be made!
You should check out this fork by the person who made CTGP7, there are portable releases