Here are a few options you could use for a tool, game, or app: 1. Pulse Planner (productivity tool)

Here is a project description for Pulse Planner: Pulse Planner is a modern productivity tool designed to synchronize your daily tasks with your natural energy rhythms. Built with React for a dynamic frontend, Node.js/Express for the backend API, and PostgreSQL for robust data persistence, it uses a smart algorithm to intelligently schedule high-focus work during your peak hours and lighter tasks during dips, maximizing efficiency without burnout.