Waveland Command Line Level Editor—edit custom level files for Waveland from the command line! Made by reverse-engineering the level file format (with help from Aetias). Video demo below.
DocComments for Neovim—Annotate sections of text with Neovim, a-la GoogleDocs comments. Demo here. I also wrote a couple scripts to convert to/from commented docx and my own format. The scripts are located here, and there is a video demo of the conversion process. I regularly use this plugin when writing prose, to add suggestions or remind myself to come back to something later.
Waveland color picker—Set the color of your vessel in Waveland to any color, even ones you can't purchase in-game.