PWABuilder - Formerly Manifoldjs, the simplest way to create progressive web apps across platforms and devices

EssentialPIM - EssentialPIM is a free Personal Information Manager that keeps up with the times and lets you manage appointments, tasks, notes, contacts, password entries and email messages across multiple devices and cloud applications.

Progressier - The No-Code Progressive Web App Toolset. Add PWA installation, offline capabilities, caching strategies, push notifications to your web app or website. No code to write.

Todo.txt - Track your tasks and projects in a plain text file, todo.txt. A todo.

ScandiPWA - React PWA to improve your e-commerce store experience

Task Coach - Task Coach is a simple open source todo manager to keep track of personal tasks and todo lists.