I have a TV that has time shift and recording functions for USB hard drive.
There is no place behind the TV to hold HDD. It just wiggles there in the air, so i made a bracket for it.

This holds Transcend StoreJet 129,5 mm × 80,8 mm × 16,1 mm and can be scaled for other models.
Use two sided sticky tape to attach behind TV, side of a computer, etc...