One of my favorites is the Dumbbell Bulgarian Split Squat - with the rear leg elevated.
HERE ARE 5 REASONS WHY:
1. It helps increase hip flexibility and balance.
2. It puts you in a position similar to how most sports are played (with one leg extended in front of the other)
3. It actually did not originate in Bulgaria.
4. Its allows you to add load to your legs without compressing the back - as opposed to what normally happens during a back squat
5. It helps build your grip - aside from variations of the deadlift, how many other lower body lifts can actually do that.
(This picture has nothing to do with grip strength, but it came up when I used Google Images to find "hands holding heavy dumbbells". I felt it was my obligation to share it with you.)
Seeing the Bulgarian Split Squat in Action
Enclosed is video of Ryan Smith performing the split squat with 90lb dumbbells.
Considering he is holding more weight, than he himself weighs, this is pretty impressive.