Check what is colliding with trigger

If I have a reference to a collider is it possible to check what it is colliding with i.e. get a list of colliders that it is touching. Basically similar functionality as OnTriggerStay without using that method exactly or the other 2 enter and exit methods. Say for example a check I could make during an update call.

You could keep track of ever collider which enters or exits your trigger:

private List<Collider> myColliders;

void Start(){
    myColliders = new List<Colliders>();
}
void OnTriggerEnter(Collider col){
    myColliders.Add(col);
}
void OnTriggerExit(Collider col){
    if(myColliders.Contains(col))
        myColliders.Remove(col);
}