Well if anyone is new to TextMate, you need to install the "Get Bundles" Bundle--a GUI to the TextMate SVN and git Bundle repositories. More detail on installing the 'Get Bundles' Bundle in an answer to a different question on SO.
I think this is the easiest way to not only view all available Bundles but also to update them on your own rig.
As of five minutes ago, Get Bundles counts 793 total TM Bundles available either in the Official TM SVN Repository or on the TM git Repository.
Once you have that, you can "go shopping"--so for instance if you're a web developer then you can quickly see that there are (at least):
six different Bundles for CSS
(including the official TM CSS Bundle
that comes pre-installed)
six Bundles for Django
six Bundles for HTML, etc.
Of course, the Web Dev framework with the largest TM user base is RoR; i quickly counted a dozen different RoR Bundles though i am sure there are more.
I use several TM Plug-ins:
MissingDrawer
SVNMate
TmCodeBRowser
TMQuickLook
WebMate