pyratemp is probably (one of) the smallest complete template-engines for Python (with about 500 LOC). It has a very small set of special syntax in the templates. This reduces complexity and the probability of bugs and lead to an easy-to-use and intuitive user-interface. It uses embedded Python-expressions (in a "sandbox"), is well documented, has full Unicode-support, and produces very good error-messages, which is very useful when creating new templates.
Relatorio is a Python opendocument templating library, based on Genshi. It provides a way to easily output severals kinds of files (odt, ods, png, svg, etc.) by using documents in any of the Open Document formats (and some others) as templates. It also includes a simple report repository.
LEPL is a recursive descent parser library written in Python. It is based on parser combinator libraries popular in functional programming, but also exploits Python language features. Operators provide a friendly syntax, and the consistent use of generators supports full backtracking and resource management. Backtracking implies that a wide variety of grammars are supported; appropriate memoisation ensures that even left-recursive grammars terminate.
Lumbricidae WORM (Widget Object Relational Mapper) is an SQLAlchemy binding for Webwidgets. SQLAlchemy presents database tables and rows as Python classes and objects. Webwidgets is a framework for writing Web applications as if they were desktop applications. WORM lets you easily map Webwidgets input fields, tables, and other widgets to database mapped classes, instances, and attributes. It requires the Argentum SQLAlchemy convenience library.