Motion Firefox - All-in-one time management tool in Firefox
FocusList - Daily planner & focus timer based on timeboxing and pomodoro
Everlist Task Manager - Groceries, trips, errands, and daily todos managed simply. get your tasks under lovely control.
Teeny Breaks - Mindfulness tips to make the most of your breaks 🧠💖
Week - Task management tool with a heavy focus on planning
Add to Calendar Link Generator - Create buttons for Google Calendar, Office 365 and Apple Cal