Filters http://jinja.pocoo.org/docs/dev/templates/#filters
Filters are functions that apply to value.
List of Builtin Filters http://jinja.pocoo.org/docs/dev/templates/#builtin-filters
Custom Filters http://jinja.pocoo.org/docs/dev/api/#custom-filters
Note: custom blocks is non-trivial in Jinja2, no example included.
Blocks http://jinja.pocoo.org/docs/dev/templates/#blocks
Blocks are used for inheritance and act as both placeholders and replacements at the same time.
Extensions http://jinja.pocoo.org/docs/dev/extensions/
Writing Extensions http://jinja.pocoo.org/docs/dev/extensions/#module-jinja2.ext