Free Alarm Clock - Free Alarm Clock is a free, full-featured and user-friendly computer alarm clock for Windows.
Simply Remind Me - Free email and text reminder service so you don't forget the important things in life!
Gnome Clocks - Clock application designed for GNOME 3
FollowUpThen - The simplest way to schedule an email reminder
AlarmDJ - Online Alarm Clock - Use YouTube videos or MP3 files as alarm sound. Works offline.
Auto Mail Sender - Auto Mail Sender Standard Edition official page. A powerful and easy-to-use eMail scheduler.