Alarmy - World's most annoying alarm app
T-Clock Redux - T-Clock Redux in an enhanced fork of Stoic Joker's T-Clock 2010 with ISO week number support...
Wake N Shake Alarm Clock - Wake up with a jolt of energy ready to get shit done.
Fitari Fitness Alarm Clock - The Fitness Alarm Clock will wake you up by making you stand up and do a number of fitness...
Wakefy - Turn your Mac into a Spotify alarm clock.
ClocX - ClocX - freeware analog clock for Windows desktop with many features like calendar, alarms, skins, antialiasing and transparency.