My faves are... (all are around 20 mins unless otherwise stated)
Jillian Michaels 30 Day Shred Level 1
Jillian Michaels Six-Pack Abs
Jillian Michaels Banish Fat, Boots Metabolism workout - just under an hour long
Jillian Michaels Yoga Meltdown (I normally find Yoga so boring but this makes you feel like you are actually doing something, you will actually sweat lol)
Denise Austin Cardio Kick Fat Burn
Denise Austin Fat Burn Pilates
Zuzka Light - search for her channel on YoutTube - her ZWOW workouts are tough, but good tough!
Let me know what you think and how you get on with any of them.