Any existing resource for die cutting patterns should be a great fit for laser cutting.
My wife has done a lot of packedge and stationary design and she is super excited about having a laser to do prototyping. (think patterns for fancy folded envelopes and paper toys).
She had a custom die made to manufacture these toys product design (available now at Ada’s books in Seattle 
) and I know that if she had a laser I would not have had to provide as many glasses of wine during the prototype phase. 
I have been collecting links to die cut patterns for a while from sites like this:
Packaging Templates
Box Templates
I also found this (somewhat hard to watch) video on how to make your own templates in Illustrator
How to make an illustrator packaging template
And finally THIS!
Template maker
(I love these online parametric generators)