Unity AddNextSprite button with OdinInspector

gistfile1.txt

using Sirenix.OdinInspector;
using System.Collections.Generic;
using System.Linq;
using UnityEngine;
using System;

public class MyUnityObject : MonoBehaviour {
    
    [InlineButton("AddNextAnimationSprite", "Add Next")]
    [PreviewField(ObjectFieldAlignment.Left, Height = 50)]
    public List<Sprite> EffectSprites = new List<Sprite>();

    public static void AddNextAnimationSprite(List<Sprite> sprites)
    {
        if (sprites == null || sprites.Count == 0) return;
        var lastSprite = sprites[^1];
        var path = UnityEditor.AssetDatabase.GetAssetPath(lastSprite);
        var objects = UnityEditor.AssetDatabase.LoadAllAssetsAtPath(path);
        sprites.Add(objects.Where(q => q is Sprite).Cast<Sprite>().First(s => s.name == lastSprite.name.IncrementNumberAfterUndescore()));
    }
}
public static class MiscExtensions
{
  public static int NumberAfterUnderscore(this string text)
	{
		return int.Parse(text[(text.LastIndexOf('_') + 1)..]);
	}
	public static string IncrementNumberAfterUndescore(this string text)
	{
		var newNumber = text.NumberAfterUnderscore() + 1;
		text = text.Remove(text.LastIndexOf('_') + 1);
		return text + newNumber;
	}
	public static string SetNumberAfterUnderscore(this string text, int number)
	{
		text = text.Remove(text.LastIndexOf('_') + 1);
		return text + number;
	}
}