Popular XML vocabularies expressed using DTD? using Relax NG? using XML Schema?

Hi Folks,

I am putting together a list of XML vocabularies that are expressed
using either DTD, Relax NG, or XML Schema.  Below is the list I have
thus far.  Can you add to the list please?

DTD
   XHTML
   Docbook

Relax NG
   SVG
   XML Dig-Sig
   Atom

XML Schema
   GML
   XSLT

Thanks!

/Roger