Lono here are myy preferred survival knives features (swiss army champ xlt)
Can you really not think of any circumstances one of these would be useful?
The Sock

Large blade
Small blade
Nail file with Metal file
Nail cleaner
Metal saw
Pharmaceutical spatula
Scissors
Wood saw
Fishscaler with hook disgorger
ruler (cm & inches)
Pruning blade
Electrician's blade with wire scraper
Case and Wrench with
-5mm female Hex drive for D-SUB connectors
-4mm female Hex drive for the bits
-Bit Phillips 0 (Pozidrive)
-Bit Phillips 1 (Pozidrive)
-Bit Slotted 4 mm
-Bit Phillips 2
-Bit Hex 4 mm
-Bit Torx 8
-Bit Torx 10
-Bit Torx 15
Pliers with
-wire cutters
-wire crimping tool
Magnifying Glass
Phillips screwdriver
Cap lifter with
-screwdriver 6 mm
-wire bender
Can opener with small screwdriver 3mm
Corkscrew
Chisel
Universal Hook (also parcel carrier)
Fine screwdriver 2 mm
Reamer
Punch and sewing eye
Key ring
Tweezers
Toothpick
Ball point pen - also to set DIP-Switches
Pin
Mini-screwdriver