SceneView Gizmos labels that don't create clutter.

CommandGizmos.cs

using System.Collections;
using System.Collections.Generic;
using UnityEditor;
using UnityEngine;

  public static class CommandGizmos
  {
      static GUIStyle sceneNote;

      static CommandGizmos()
      {
          sceneNote = new GUIStyle("box");
          sceneNote.fontStyle = FontStyle.Bold;
          sceneNote.normal.textColor = Color.white;
          sceneNote.margin = sceneNote.overflow = sceneNote.padding = new RectOffset(3, 3, 3, 3);
          sceneNote.richText = true;
          sceneNote.alignment = TextAnchor.MiddleLeft;
      }

      static void DrawNote(Vector3 position, string text, string warning = "", float distance = 10)
      {
          if (!string.IsNullOrEmpty(warning))
              text = $"{text} <color=red>{warning}</color>";
          if ((Camera.current.transform.position - position).magnitude <= distance)
              Handles.Label(position, text, sceneNote);
      }

      [DrawGizmo(GizmoType.InSelectionHierarchy | GizmoType.NotInSelectionHierarchy, typeof(Teleporter))]
      static void DrawTeleporterGizmos(Teleporter teleporter, GizmoType gizmoType)
      {
          if (teleporter.destinationTransform)
          {
              DrawNote(teleporter.transform.position, "Teleport Enter");
              Handles.color = Color.yellow * 0.5f;
              Handles.DrawDottedLine(teleporter.transform.position, teleporter.destinationTransform.position, 5);
              var direction = Quaternion.LookRotation(teleporter.destinationTransform.position - teleporter.transform.position);
              DrawNote(teleporter.destinationTransform.position, "Teleport Exit");
          }
          else
          {
              DrawNote(teleporter.transform.position, "Teleport Enter", "(No Destination!)");
          }
      }
  }