The Gerber Dime packs eight tools into a keychain-sized multitool that’s less than 3" long when closed, and you can grab one for $12 from REI today.
Note: You can choose in-store pickup for free, or get free shipping with a $50 purchase. If you don’t live near an REI and don’t want to buy anything else, you can get it from Amazon with Prime shipping for a few bucks more, though the price varies by color.