KEVIN HAMMOND of DB Services mentioned in his FileMakerProGurus video interview that his favorite FileMaker Plugin was BaseElements:
The BaseElements plugin is a free and open source plugin, available to everyone to extend the built in functions of FileMaker Pro. Originally conceived to replace two separate plugins for our developer tool BaseElements, we've since extended and adapted it further and it now has may functions beyond it's original plan.
The BaseElements plugin has functions for file manipulation, dialogs, XSLT operations, clipboard manipulation, performing shell scripts and FileMaker scripts, internal SQL operations, MD5 and SHA hashing and more. A full list of the functions and the details of them is available on the wiki page.
The list of functions included with Base Elements is incredible:
XSLT and JSON
- BE_ExecuteShellCommand Deprecated
Best of all, Base Elements is completely free–although Goya will accept donations at their website. You are free to use it, extend it, rename it, and re-compile it. It doesn't get much better that that. Visit their site for full details.