@aparrish
Orientdb - privately held, but Java
ArangoDB - C++ but VC-backed (no IPO yet)
Dgraph - new, interesting, lacks sufficient docs
Tidb - NoSql but speaks MySql wire protocol so you can use most mysql/maria clients and get NoSql too
Redis - you probably know about aleeady
Not really scrappy things, there's scrappier ones, but thesenwork pretty well already