I maintain and/or contribute to a number of tools that certain people might find interesting.
I've made some contributions to Martin Thomson's fantastic I-D Template, which is a toolchain for integrating various tools to author IETF drafts (and eventually RFCs) in Markdown. Lots of neat integration with GitHub, with support for GitHub Actions, etc.
One of my contributions has split out into its own small project, archive-repo. It attempts to solve the problem that GitHub offers more features than "just" a git repo; issues, PRs, reviews, discussions, etc. Those are useful, but they break the principle that everyone who clones a copy of the git repo has the whole thing. This tool lets you suck down a lot of that GitHub-specific information into a JSON file. Check the file into the repo, and now everyone who clones the repo actually does have a recent copy. I-D Template runs this tool as part of its CI actions.
This is mostly work-funded.
I've contributed a fair bit to Nathan Gardiner's fork of TWCManager, which is now far more active than the original version. I largely maintain the Tesla Powerwall and Vehicle API modules, with occasional tweaks to the main logic and the HTTP interface to support other things I'm working on.
I wrote a module for Michael Teeuw's MagicMirror2 software, MMM-Powerwall, which integrates with the Tesla Powerwall's local interface, the Tesla API, and TWCManager. The module displays real-time information about your home's energy use (as measured by the Powerwall) as well as recent historical information (as recorded by the Tesla API).
Since Tesla is making it harder and harder to implement authentication to their APIs directly in these and many third-party programs, I wrote a Windows app to simplify retrieving authentication tokens. (There are comparable apps for Android and iOS, which I did not write.)