One that I use pretty often is `sortedcitations.lua`, which sorts the citations in a LaTeX file according to their appearance in the text. There are lots of fancy tools and bibliography management, BiBTeX, etc, but in the vast majority of cases I just want a single file with the citations in the right order.

https://gist.github.com/scythe/7cea80364bacf1f1ce6a67786bcbc...