3. Angus MacGyver (MacGyver)
For this one, we're going old school. MacGyver wouldn't necessarily make a good Avenger, per se, but he would definitely interest SHIELD. If SHIELD were impressed with what Tony Stark did with a tailor-made list of parts in a cave, imagine how impressed they'd be with MacGyver. This is a guy who made bombs using cough sweets; a defibrillator using candlesticks, a microphone cord and a rubber mat; a lie detecting machine using a blood pressure cuff, a stethoscope and an alarm clock; and a hot air balloon using home-made glue, random scraps of nylon, a metal shed and some gas canisters. He's not a guy who they'd use out on the streets of New York to fight off an alien invasion, but he'd sure be a useful member behind the scenes with SHIELD's resources at his disposal.