who can drop all items

[elevenlang]

inferno regular monster? elite? boss?
hell diablo?

[spolja]

All of them (with a certain percentage).
Note that, in order to get lvl63 affixes on items, you must play on ACT III MP0 difficulty or higher.

[Karth]

No monster in the game can drop all of the items in the game. They all have a minimum - maximum range of item levels they can drop.

As for what can drop the highest level (ilvl 63) items, anything in inferno on MP1+, or A3 and A4 on MP0.