Microsoft XML Parsers for Microsoft's IE4
 
Netscape Demo of XML Parser in Java
 
Datachannel XML Tools
Sun's HTML Parser
 
It may not that perfect. (Only for HTML, not all SGML
features)
Class Parser of Swing
 
javax.swing.text.html.parser.Parser
 
This may parse only SGML/HTML.
Clyde Virtual University's web-site HTML parser
Caucho XML Parser
 
This is part of
resin 1.0
HEX - The HTML Enabled XML Parser(Hewlett Packard)
 
An HTML parser. It doesn't understand either SGML or XML DTD's...
SwTech's XML Parsers and Development Tools
 
This page also has a list of parsers.
IBM's XML Parser for Java
Supporting XML, DOMHash, and DOM.
StudioM's XML Parser for Java