Unity EditorButton attribute that shows buttons of methods in the inspector.

EditorButtonAttribute.cs

using System;
using System.Linq;
using System.Reflection;
using UnityEngine;

#if UNITY_EDITOR
using UnityEditor;
#endif

namespace AnimalCompany
{
    [AttributeUsage(AttributeTargets.Method, AllowMultiple = false)]
    public class EditorButtonAttribute : Attribute
    {
        public string Label { get; }

        public EditorButtonAttribute() : this(label: null) { }
        public EditorButtonAttribute(string label)
        {
            Label = label;
        }
    }

#if UNITY_EDITOR
    [CustomEditor(typeof(MonoBehaviour), true)]
    public class EditorButtonDrawer : Editor
    {
        private MethodInfo[] _buttonMethods;
        private EditorButtonAttribute[] _buttonAttributes;

        private void OnEnable()
        {
            _buttonMethods = target
                .GetType()
                .GetMethods(BindingFlags.Static | BindingFlags.Instance | BindingFlags.Public | BindingFlags.NonPublic)
                .Where(m => m.GetCustomAttribute<EditorButtonAttribute>(inherit: true) != null && m.GetParameters().Length == 0)
                .ToArray();
            _buttonAttributes = _buttonMethods
                .Select(m => m.GetCustomAttribute<EditorButtonAttribute>(inherit: true))
                .ToArray();
        }

        public override void OnInspectorGUI()
        {
            base.OnInspectorGUI();

            if (_buttonMethods == null || _buttonMethods.Length == 0)
                return;

            GUILayout.Space(10f);

            for (int i = 0; i < _buttonMethods.Length; i++)
            {
                EditorButtonAttribute attribute = _buttonAttributes[i];
                if (attribute != null)
                {
                    GUILayout.Space(5f);
                    MethodInfo method = _buttonMethods[i];
                    if (GUILayout.Button(attribute.Label ?? method.Name))
                    {
                        method.Invoke(target, null);
                    }
                }
            }
        }
    }
#endif
}