vital.vim (GitHub: vim-jp / vital.vim, License: NYSL) from the Japanese Vim User Group is a collection of useful Vim functions. It includes libraries for assertions, various data types, SQLite, options parsing, JSON, XML, and more.
Modules can be installed with
:Vitalize, and functions can be imported with
From what I can tell, most of the modules are written in Vim script rather than using another scripting language like Python. The XML.vim module has Vim script functions for parsing XML trees and navigating the child nodes.