Ramune and lemon vinegar flavors.
Around the time that I left Japan, Nestle Japan seemed to be changing their marketing strategy. The days when they regularly (and somewhat frequently) released bizarre one-off flavors seem to be over. There is still the occasional freaky flavor as well as the regional offerings, but the treadmill of weirdness has stopped.
That doesn't mean that I don't miss these strange flavors. What it means is that I'd miss them to some extent even if I was still in Japan!