Soccer Tracker
Track players time in and out of the game and their positions. Also, you can take notes for games.
You can sign in at https://soccer.jnyman.com
From a technological point of view this is an interesting project since it is an offline-first web application which auto syncs with the back end (if signed in). It uses the library HTMZ which makes development straight forward and fast but makes the application feel like an SPA.