SCP-127 - The Living Gun
SCP-127 features two settings: semi-automatic and fully automatic (an audible groan can be heard when switching between the two).
SCP-117 - Complete Multitool
However, if the user is faced with a specific task, regardless of what tool the subject intends to pull out and use, a tool perfectly fit for the task at hand will take its place.
SCP-50-AE-J - The Deagle
Investigations into the further properties of SCP-50-AE-1 have been stymied by the fact that SCP-50-AE-1 continues to attack Foundation scientists, calling them "PINKO F*CKS".
SCP-1543-J - The Sun Launcher
Painted on the side is the motto, in large capital letters, “When in doubt, launch into the sun” (which some feel can never match the flair of the SCP’s old creed, “Into the fiery orb with ye”).
SCP-044 - World War II Era Molecular-Fission Cannon
Any object or pile of objects that fits may be loaded into SCP-044’s muzzle to be used as ammunition.
SCP-034 - Obsidian Ritual Knife
…The individuals who have their flesh cut off by SCP-034 must still be biologically alive to maintain the facade.