10. Abigail Brand And S.W.O.R.D.
In the comics, the Sentient World Observation and Response Department (S.W.O.R.D.) is an offshoot of S.H.I.E.L.D. tasked with dealing with extraterrestrial situations. S.W.O.R.D. is led by Abigail Brand, an alien/human hybrid and operates out of an orbiting space station called The Peak. The relationship between S.W.O.R.D. and S.H.I.E.L.D. is strained on the best days and brand tends to act like she is head of an independent operation instead of a subdivision of S.H.I.E.L.D. Agents of S.H.I.E.L.D. could really make good use of S.W.O.R.D. and the Abigail Brand character. On the show Brand could have the same level of clearance as Agent Coulson and the two of them could have a longstanding professional rivalry. S.W.O.R.D. and Brand could be introduced in an episode where Coulson and his team answer a distress call from a S.H.I.E.L.D. outpost that has become overrun by the Brood (think the aliens from Alien and you have a perfect idea of what the Brood are) and Brand gets called in because she is an expert on extraterrestrial life-forms. From there hilarity ensues.