Extending Zotero with Plugins
There are a lot of plugins and extensions for Zotero, ranging from small tweaks of particular features to major customisations; just a few examples are listed here.
They are great things, facilitated by the open source nature of Zotero, but a caveat is in order. Plugins are not guaranteed to be as well-maintained (or documented) as Zotero itself; they can sometimes be buggy or they may break following updates to Zotero (or to Firefox, or any other software they might depend on). And, while Zotero itself is no longer wedded to Firefox, quite a lot of plugins are still Firefox-only.
The examples here are either well-established and/or ones I’ve tried out and could get to work (though not necessarily at the first attempt…). I have not tested most of the additional examples listed in the bibliography!
Utilities
Zutilo - adds a number of small but often handy enhancements to the Zotero interface.
Managing files and attachments
Zotfile - includes ability to rename and attach files, and extract annotations from PDFs into notes.
For websites
Zotpress - display your Zotero bibliographies on a Wordpress website.
There are also a number of useful plugins to Zoterify your Wordpress website by embedding metadata (try searching the plugins directory for “metadata”, “dublin core”, “COINS”, etc), which is well worth doing if you can.
Specialised extensions
Juris-M: support for legal and multilingual scholarship - “a research environment that is based on, but separate from, the well-known Zotero reference manager. It adds support for legal materials, legal citation styles, and multilingual materials.”
Analysing data
Paper Machines - analysis and visualisations of Zotero libraries and HTML/PDF/text attachments. (At the time of writing, I believe this plugin is not functional.)