"aura" is a desktop (X root window) background setter. It picks images randomly from specified paths, skipping those that are too small or have inappropriate aspect ratios, and rescales them by cropping solid margins, resizing with cubic interpolation and then the liquid rescale algorithm to fit the desktop with as little quality loss as possible. Images are labelled in the corner using embedded tags. It can changes images on a timed basis or when triggered by SIGHUP or the CLI, and tracks previous and blacklisted images.
excat is a simple tool that auto-detectd (potentially nested) compressed file formats and decompresses any combination of them using libarchive, thus unifying zcat, bzcat, lzcat, xzcat, etc. in a single (static, if you need it) binary. It may act as a drop-in replacement for any *cat.
image-deduplication-tool is a script designed to scan specified paths and calculate the DCT hashes of all the images there. It compares the hashes to find closest-looking image pairs, despite various alternations (such as crop, rotation, gamma/color correction, noise, etc.), optionally presenting them in a feh image viewer for the operator to easily compare and remove one of the versions. It uses libpHash to produce and compare perceptual hashes.
notification-thing is a full-featured implementation of the Desktop Notifications Specification. It is not tied to any specific desktop environment, and is focused on features like rate-limiting and flexible filtering to minimize distraction and noise ratio in a transparent way, without silently dropping anything ever.
pulseaudio-mixer-cli is an interactive ncurses UI to control the volume of PulseAudio streams. It is somewhat like alsamixer, but focused not on sink volume levels (which can actually be controlled via alsamixer, with the alsa-pulse plugin), but rather on the volume of individual streams from applications, allowing the user to balance sound levels between them. Interaction with pulseaudio is done through the DBus interface, and the UI is designed to be as simple as possible, without heavy DE dependencies like GNOME libs or KDE/QT.
snmpd-pyagentx provides Python3 bindings for AgentX extension of the snmpd part of the Net-SNMP project. It allows you to tie into snmpd, returning your own values for OIDs or whole OID trees right from the Python code. It consists of a thin C interface for snmp_agent_api(3), provided by net-snmp project libraries, and pure Python logic for handling forwarded requests. The C code is loosely based on the python-agentx project codebase by Bozhin Zafirov.