You should add RethinkDB! I moved to it from MongoDB years ago.
The built-in Data Explorer is a must-have for me and idk of any other database that has something similar.
I used RethinkDB back in the days because it was the first DB that had pretty good replication and sharding - it was zero effort. I felt the functional programming model to be strange, some stuff got executed locally, other parts remotely and it was not very straight forward when things didn't go as planned.
By the time the RethinkDB company folded, CockroachDB emerged and has been my go-to distributed DB since.
They don't use a key-value store library.
I know it's a bit of a fine line. But I'm talking about standalone libraries people embed across different applications/databases. That's what RocksDB/LevelDB/Pebble are.
[0] https://github.com/rethinkdb/rethinkdb/tree/v2.4.x/src/btree
> Yeah, there's no workaround that I can find for 3.4 (duplicate effects), 3.5 (read skew), 3.6 (cyclic information flow), or 3.7 (read own future writes). I've arranged those in "increasingly worrying order"--duplicating writes doesn't feel as bad as allowing transactions to mutually observe each other's effects, for example. The fact that you can't even rely on a single transactions' operations taking place (or, more precisely, appearing to take place) in the order they're written is especially worrying. All of these behaviors occurred with read and write concerns set to snapshot/majority.