Render Markers is a Blender addon that renders and instantly saves frames carrying markers. It sits in the Render Panel, and to get started you only need a marker in your scene and an output directory. From there, the addon can be executed with a customizable shortcut key.
Each marker render is auto-saved to the Blender Output directory, and only frames with markers are processed. Frames without markers are skipped, so you don't have to sort through renders you don't need before finding the ones you want.
This makes it suited to storyboarding, grease pencil, comics, and many more workflows. Render Markers is listed for Blender version 3.3, distributed under the GPL license, and was made with the help of Serpens. You can find it in the Superhive library.