LIMITER by AvTechNO is a personal favorite of mine. I'm a huge fan of trance-like elements in music, and the electronic instrumentals incorporate Luka and Len's robotic vocals well enough to the point they don't feel out of place or unnaturally generated like a lot of vocaloid songs do. Just feels like autotuned trance, yeah.
I don't really listen to vocaloid a whole lot--didn't know many song back when they exploded in popularity, and don't really seek out new songs now--but I keep a couple of favorites on my phone. LIMITER takes me back to the good parts of 2013, so it's a good song to reminisce with.