CSHARP

unity interfaces

// When you use an interface, you can use two diferent objects to perform one 
// action in common that executes diferently in each of theme.

Interface IDrivable {
	void Drive(); //just the sentence
    //....
}

// Examples of uses:

class Car1 : IDrivable
{ 
	void Drive() {
	//actions to drive the first Car
	}
}

class Car2 : IDrivable
{
	void Drive() {
	//actions to drive the second Car
	}
}

// In this example Car1 and Car2 are diferent classes and each of theme
// drives diferently, but can be used in something like this:

public IDrivable CarToDrive;
CarToDrive.Drive() // this executes Drive() in the selected car, no methers
					// what car is.

unity run all interfaces

 using System.Linq;   
 ...    
              var ss = FindObjectsOfType<MonoBehaviour>().OfType<IStats>();
              foreach (IStats s in ss) {
                  enemies.Add (s);
              }