Mark O'Sullivan and Todd Burry are the lead developers behind Vanilla & Garden, but there is an entire community of people who make this thing work.

Taking from the blog about section on the right.

There have been quite a few contributors to the core of vanilla and plugins being written all the time.

http://github.com/lussumo/Garden/commits/master
The link may give you some idea of who's committing what to vanilla itself.