TxMongo was created by Alexandre Fiori who developed it during the years 2009-2010. From 2010 and onwards mainly bug fixes were added, as Alexandre entered maintenance mode with many contributions being made by others. Development picked back up in 2014 by Bret Curtis with Alexandre's consent and was migrated to Twisted where it is a first-party Twisted library. TxMongo can be found here:
https://github.com/twisted/txmongo
The MongoDB client library functionality is in active use. It is stable and works very well.