This is a paid asset, but now you can download Navigation2D (Pathfinding for 2D Games) Free.
Detail this asset from Unity Store: Original Link
Navigation2D (Pathfinding for 2D Games) v1.30 (Latest version)
“If possible, please buy the package to support the developer”
Navigation2D uses Unity’s built-in Navigation system to make 2D pathfinding possible without any axis rotations.
1. Make 2D Colliders static
2. Go to Navigation2D, select Bake
3. Use NavMeshAgent2D to move
* Uses built in BoxCollider2D
* Uses built in CircleCollider2D
* Uses built in EdgeCollider2D
* Uses built in PolygonCollider2D
* Uses built in TilemapCollider2D
* Wraps NavMeshAgent for 2D
* Wraps NavMeshObstacle for 2D
Successfully used by uMMORPG 2D!
Try the WebGL Demo to see it in action!