The most common elements in the Death tattoos are, without any doubt, the weapons (for the obvious reason that they are used for killing people).
The scythe is, by far, the most popular choice when it comes to a Grim Reaper tattoo. The scythe can symbolize the cutting of negative energies or influences. Also, as a harvesting tool, it can symbolize hope and prosperity. It can represent the moment of death, when a scythe is said to cut a silver thread. The scythe has a long handle, indicating that it can reach anywhere.
However, when the Death is portrayed as the Death Angel, the scythe is usually (but not necessarily) replaced by a sword. The sword can be a short, simple, sword (similar to the roman Gladius) or a highly-decorated sword.
Without being very popular, many other medieval weapons can be seen in the Death tattoos: spears, lances and javelins (these weapons can be seen in the Angel of Death tattoos or in the tattoos which depict Death as a medieval knight), knives and daggers (very common in the Skulls tattoo designs), bows and arrows, etc.
Increasingly popular are the fire-guns: usually handguns - derringers, old-fashioned revolvers (very common in the Mexican Mafia tattoos and in the Skulls tattoos), semi-automatic pistols and machine pistols (very common in the gang / prison tattoos) but also various long guns (like shotguns or sniper rifles).
skull tattoo covering a man's chest: a skull and two crossing revolvers surrounded by several gunshot wounds