Streaks - The to-do list that helps you form good habits.
Free Alarm Clock - Free Alarm Clock is a free, full-featured and user-friendly computer alarm clock for Windows.
Taskful - Deadlines, meet your match.
Digital Clock 4 - Beautiful customizable clock with plugins
ToDoList - Windows desktop application to stay on top of your daily tasks.
AlarmDJ - Online Alarm Clock - Use YouTube videos or MP3 files as alarm sound. Works offline.