The Oxygen XML Editor is a multi-platform XML editor, XSLT/XQuery debugger, and profiler with Unicode support. The folks over at SyncroSoft have added MarkLogic support into their Oxygen XML Editor. This includes:
Beyond the Oxygen client itself, they also distribute an Eclipse plug-in that exposes the same functionality in Eclipse.
Those interested in developing and testing XQuery may also want to take a look at Overstory’s IntelliJ plugin. This plugin povides support for XQuery language version 3.0 and 3.1 in IntelliJ IDEA.