Preallocate Collection Capacities

The Tip: Initializing generic collections via new List<T>() causes automatic background array resizing and heap allocations as items are added.

How to Use: Pass the expected element count into the list constructor upfront.

using System.Collections.Generic;
using UnityEngine;

public class ParticlePool : MonoBehaviour
{
    // Allocates fixed storage upfront, eliminating dynamic array expansion GC
    private List<GameObject> activeParticles = new List<GameObject>(500);
}