Claudia Schiffer workout videos! They are only available in VHS (came out about 15 years ago) but I did a search and apparently they show up in youtube.

She had 4 videos: arms, abs, buns and legs. The buns one is the best workout for that area that I have ever done and when I do it I see results after one or two weeks. Arms also highly recommended.

What I particularly like about her workouts is that they are solid routines and under 30 minutes. I find most of the more recent workout videos quite diluted with aerobics.