Custom Odin Attribute

MyMono.cs

public class MyMono: MonoBehaviour {
  [SelectAsset(SelectFileType.GameObject, "Assets/", "collider", ".wav|.prefab")]
  public string MyPrefab;
	
  [SelectAsset(SelectFileType.AudioClip, "Assets/Resources/BGM/", "", ".wav|.mp3")]
  public string MyAudioClip;
}

SelectAssetAttribute.cs

public enum SelectFileType
{
	GameObject,
	AudioClip
}

public class SelectAssetAttribute : Attribute
{
	public SelectFileType SelectFileType;
	public string Directory;
	public string Prefix;
	public string[] Extensions;

	public SelectAssetAttribute(SelectFileType selectFileType, string directory, string prefix = "", string extension = "")
	{
		SelectFileType = selectFileType;
		Directory = directory;
		Prefix = prefix;
		Extensions = extension.Split('|');
	}
}

SelectAssetAttributeStringDrawer.cs

using System.Text.RegularExpressions;
using Quantum.Attributes;
using Sirenix.Utilities.Editor;
using UnityEditor;
using UnityEngine;

namespace Sirenix.OdinInspector.Editor.Drawers
{
  [DrawerPriority(0.3, 0.0, 0.0)]
  public sealed class SelectAssetAttributeStringDrawer : OdinAttributeDrawer<SelectAssetAttribute, string>
  {
    private static int _controlIdCounter = 0;
    private int _controlId = 0;
    private Object _invalidSelectedObject;
    
    protected override void DrawPropertyLayout(GUIContent label)
    {
      IPropertyValueEntry<string> valueEntry = this.ValueEntry;
      this.CallNextDrawer(label);

      // show asset dialog
      if (GUILayout.Button($"Select in {Attribute.Directory}"))
      {
        _controlId = ++_controlIdCounter;
        if(Attribute.SelectFileType == SelectFileType.GameObject)
            EditorGUIUtility.ShowObjectPicker<GameObject>(null, false, Attribute.Prefix, _controlId);
        
        if(Attribute.SelectFileType == SelectFileType.AudioClip)
            EditorGUIUtility.ShowObjectPicker<AudioClip>(null, false, Attribute.Prefix, _controlId);
      }

      // select the object
      string commandName = Event.current.commandName;
      if (commandName == "ObjectSelectorClosed" && EditorGUIUtility.GetObjectPickerControlID() == _controlId)
      {
        var selectedObject = EditorGUIUtility.GetObjectPickerObject();
        if (selectedObject != null)
        {
          AssetDatabase.TryGetGUIDAndLocalFileIdentifier(selectedObject.GetInstanceID(), out string guid,
            out long file);
          {
            var path = AssetDatabase.GUIDToAssetPath(guid);
            Debug.Log($"Selected File: guid: {guid}, path: {path}, file: {file}, name: {selectedObject.name}");
            var result = (MatchPattern(path, Attribute.Directory, Attribute.Extensions));
            if (result != null)
            {
              valueEntry.SmartValue = selectedObject.name;
              _invalidSelectedObject = null;
            }
            else
            {
              valueEntry.SmartValue = "";
              _invalidSelectedObject = selectedObject;
            }
          }
        }
      }

      if (_invalidSelectedObject != null)
      {
        SirenixEditorGUI.ErrorMessageBox($"Invalid selected object: {_invalidSelectedObject.name}");
      }
    }

    private string MatchPattern(string path, string directory, string[] extensions)
    {
      foreach (var extension in extensions)
      {
        var pattern = "" + directory + "(.*)" + extension;
        Match m = Regex.Match(path, pattern, RegexOptions.IgnoreCase);
        if (m.Success)
        {
          if (m.Groups.Count > 1)
          {
            return m.Groups[1].Captures[0].ToString();
          }
        }
      }

      return null;
    }

    private Object GetPrefab(string directory, string filename, string[] extensions)
    {
      if (filename != "")
      {
        foreach (var extension in extensions)
        {
          var path = directory + filename + extension;
          var asset = AssetDatabase.LoadMainAssetAtPath(path);
          if (asset != null)
            return asset;
        }
      }

      return null;
    }
  }
}