Feel free to add to this list.
Make your own client API. It's easy! The 1.3 protocol doc gives a complete description of the beanstalk protocol.
Note: as of version 1.0 the protocol will remain compatible until beanstalkd 2.0. Any client written to work with a 1.x beanstalkd will also work, unchanged, with any later beanstalkd before 2.0.
You can find the bleeding-edge latest protocol.txt in git.
Are listed on this wiki page.