GameObject.FindGameObjectsWithTag

static function FindGameObjectsWithTag (tag : String) : GameObject[]

Description

Returns a list of active GameObjects tagged tag. Returns null if no GameObject was found.

Tags must be declared in the tag manager before using them.

JavaScript
    // Instantiates respawnPrefab at the location 
// of all game objects tagged "Respawn".
var respawnPrefab : GameObject;
var respawns;
function Start()
{
if (respawns == null)
GameObject.FindGameObjectsWithTag ("Respawn");
for (var respawn in respawns)
Instantiate (respawnPrefab, respawn.transform.position, respawn.transform.rotation);
}

using UnityEngine;
using System.Collections;

public class example : MonoBehaviour {
public GameObject respawnPrefab;
public Object respawns;
void Start() {
if (respawns == null)
GameObject.FindGameObjectsWithTag("Respawn");

foreach (Object respawn in respawns) {
Instantiate(respawnPrefab, respawn.transform.position, respawn.transform.rotation) as GameObject;
}
}
}

import UnityEngine
import System.Collections

class example(MonoBehaviour):

public respawnPrefab as GameObject

public respawns as Object

def Start():
if respawns == null:
GameObject.FindGameObjectsWithTag('Respawn')
for respawn as Object in respawns:
(Instantiate(respawnPrefab, respawn.transform.position, respawn.transform.rotation) as GameObject)

Another example:
JavaScript
    // Print the name of the closest enemy
print(FindClosestEnemy().name);

// Find the name of the closest enemy
function FindClosestEnemy () : GameObject {
// Find all game objects with tag Enemy
var gos : GameObject[];
gos = GameObject.FindGameObjectsWithTag("Enemy");
var closest : GameObject;
var distance = Mathf.Infinity;
var position = transform.position;
// Iterate through them and find the closest one
for (var go : GameObject in gos) {
var diff = (go.transform.position - position);
var curDistance = diff.sqrMagnitude;
if (curDistance < distance) {
closest = go;
distance = curDistance;
}
}
return closest;
}

using UnityEngine;
using System.Collections;

public class example : MonoBehaviour {
GameObject FindClosestEnemy() {
GameObject[] gos;
gos = GameObject.FindGameObjectsWithTag("Enemy");
GameObject closest;
float distance = Mathf.Infinity;
Vector3 position = transform.position;
foreach (GameObject go in gos) {
Vector3 diff = go.transform.position - position;
float curDistance = diff.sqrMagnitude;
if (curDistance < distance) {
closest = go;
distance = curDistance;
}
}
return closest;
}
void Example() {
print(FindClosestEnemy().name);
}
}

import UnityEngine
import System.Collections

class example(MonoBehaviour):

def FindClosestEnemy() as GameObject:
gos as (GameObject)
gos = GameObject.FindGameObjectsWithTag('Enemy')
closest as GameObject
distance as single = Mathf.Infinity
position as Vector3 = transform.position
for go as GameObject in gos:
diff as Vector3 = (go.transform.position - position)
curDistance as single = diff.sqrMagnitude
if curDistance < distance:
closest = go
distance = curDistance
return closest

def Example():
print(FindClosestEnemy().name)