Back in 2015 I needed a convenient & fast post-processing and image alignment tool for (mainly) astrophotography time lapses, that's how ImPPG was born [1, 2]. (If GIMP had had high-bit-depth support back then, I'd probably try to write a plugin instead.) I still use it, and make small additions every now and then. It's seen some use in the community (probably mainly for solar imaging); GitHub reports a couple thousand downloads for the release that's been up the longest.