How about this:
It is assumed that the infiltrator is good enough to collect weaponry for himself, should he be in need of it. So he should carry specialized stuff that can't be easily localized during missions.
I guess a bunch of strong futuristic explosives would fit. Perfect to destroy walls or entire buildings, depending on the setting used.
There'd also be the obvious temporary buffs - Strength, Speed, armor and cloak.
Speed has the added benefit of increasing reaction speed, meaning bullet time animation.
Minor stuff would be all kinds of software - Scanning materials, translating text, etc.
Built-in equipment could be dart launchers in the wrists, used to apply poisons or something.
