The tiger is pretty different from other tanks in that it did not carry external storage hardly ever, oil and gas drums most common seen.

 Part of reason is it's design. To the rear are all the vents and filter system and really can't put anything over those. On the deck there is no space where something would not interfere with main gun. On the front lower deck section almost anything would interfere with vision block or front machine gun.

What is left is main turret that depending on version has stuff on sides already and if you put much there it can snag on top part of main deck.

That just leaves the top or the storage container to the rear. Most goas there or in tank, it might have some on top of turret but I have never seen a picture of anything on top of turret. I think standard practice was nothing on top that would obscure vision to front or sides.