Here are some scripts I've written. They're not all necessarily part authoring tools, but if anyone else finds them useful I suspect it'd be the part authoring crowd.
LDMerge - Command line script to combine LDraw directories. It keeps of record of changes which can be used to "undo" the merge. Primarily useful for temporarily merging unofficial parts with official library in order to use programs that don't recognize the /Unofficial directory.
LDTrim - Command line utility to reformat LDraw code (trim whitespace, justify columns, strip extraneous zeros, etc). Most of this can be done with LDDP but it's handy to have options.
"Export to LDraw" plugin for Google Sketchup - Derived from example by Jim Foltz.
LDMerge - Command line script to combine LDraw directories. It keeps of record of changes which can be used to "undo" the merge. Primarily useful for temporarily merging unofficial parts with official library in order to use programs that don't recognize the /Unofficial directory.
LDTrim - Command line utility to reformat LDraw code (trim whitespace, justify columns, strip extraneous zeros, etc). Most of this can be done with LDDP but it's handy to have options.
"Export to LDraw" plugin for Google Sketchup - Derived from example by Jim Foltz.