NuoDB used to be NimbusDB. As far as I can tell NuoDB release one was in January this year.

The NewSQL arena seems to have had quite a few products that have come and gone in a very short timespan.

Some of the so-called NewSQL offerings are niche engines for MySQL or offer some form of sharding for MySQL. For some reason MySQL Cluster gets lumped into the NewSQL bucket.

There are some interesting developments out there for the MySQL engines, notably TokuDB with its fractal indexes.

So far the NewSQL DB that seems to crop up most often and appears to have been around the longest is VoltDB. There are lots of positive stories surrounding that particular product as opposed to no stories for the others.