While a small blade and other simple tools do come in handy at times, why carry around a separate multitool when you're already using a keychain? That's the thinking behind the all-in-one KeySnap carabiner, which is currently on Kickstarter.
The KeySnap|Titanium EDC Multitool Keychain Carabiner by MTI
KeyUnity KB00 Titanium Sling Clip Hook, Snap Clasp
Titanium KeySnap combines a carabiner, keychain and blade
Titanium KeySnap combines a carabiner, keychain and blade
The KeySnap--Titanium EDC Multitool Keychain
The KeySnap|Titanium EDC Multitool Keychain Carabiner by MTI
Titanium Edc Keychain Bolt Carabiner / with adapter for 7 keys
Multitools
BLANK FORCES — HyperLink Titanium EDC Carabiner
KeySnap titanium EDC multitool carabiner - Geeky Gadgets