Firefox Extensions to Periodic reminders

ActiveInbox transforms your Gmail inbox into a powerful task manager, helping you prioritize emails, manage projects, and achieve Inbox Zero with a Getting Things Done (GTD) approach directly within your familiar email environment.

TickTick is a powerful cross-platform to-do list and task management application designed to help individuals and teams organize tasks, manage time, and track habits effectively. With robust syncing capabilities and integrations, it streamlines productivity across various devices.