Bottle.py: uber-fast and simple python web microframework, about 3x faster, saner, and more memory-efficient than Flask in my experience: https://github.com/bottlepy/bottle
Fossil: distributed version control and much more in a single executable, from the creators of SQLite: https://fossil-scm.org/
In the same vein, I'd name Tornado (www.tornadoweb.org). Also rather small and comprehensible, but with full async support that's evolved extremely nicely. Generally I love how well-designed and maintained it is.
Fossil: distributed version control and much more in a single executable, from the creators of SQLite: https://fossil-scm.org/