For me: SAK Rover, given to me by a drug rep many years ago when they were still allowed to give stuff. Princeton Tec Pulsar II Fox 40 Micro Whistle (In case I get trapped in the elevator....again..) Pillfob with aspirin and mortin
ALWAYS either a SwissTech Utilikey, or a Swiss Army Rambler keychain knife (it has a much more useful tool selection for its size than most.) OFTEN a AAA or coin battery flashlight, especially if I'm on the road or out at night but I usually use my cell phone for this. SOMETIMES a tubular aluminum whistle and/or a lighter of some sort, especially on a trip, hike, camping, etc. I used to carry a pen on the keyring, but I modified it for wallet carry so I can pull out the wallet and access the pen and scratch paper at the same time.
I don't carry anymore keychain-sized tools anywhere. I just carry the Vic Swisstool Spirit & Wenger Evowood S557 in the briefcase.
A couple of USBs - for the geek in me A bolt with some duct tape around it - you never know! A Gerber manicure set, with flashlight - got to look sharp, even in the dark and something from AOTDDOR - has screwdrivers, tweezers, cutter on it. all hanging off a S-Biner KeyRack and Bottle Opener - for when I want to crack open a cold one.
