Hi. You might want to search the
official forum and/or
reddit for some recommended addons. You may not get a lot of responses here because the authors are modest and don't want to brag about their own work. They maybe don't want to promote someone else's addon either for similar reasons. I'm just guessing about this. I'm not an addon author but if I were this would be on my mind.
I'm not sure if there are addons specific to Nightblade per se, but if you'd like a list of the ones I'd hate playing without the most, then message me and I'll share them. But you really will find a lot of good comments on this at forum and reddit.