This is a paid asset, but now you can download Ultimate Outlines & Highlights for FREE, but please remember this package is provided only for learning purposes or to be able to test before buying the product, NOT FOR COMMERCIAL PURPOSES.
Detail this asset from Unity Store: Original Link
Ultimate Outlines & Highlights v2.3 (Latest version)
Ultimate Outlines & Highlights v2.2
Take your game to the next level with this asset. It enables you to effortlessly add effects such as outlines, glows, overlays, and fresnel effects into any game object.
Make your in-game objects stand out, enhance gameplay, and infuse your game with an immersive feel. Select from a diverse range of options to fine-tune the appearance and make it uniquely yours.
Easily add custom selection highlighting to your models, whether they are simple or complex.
Choose from a wide range of options to tweak the appearance and make it your own.
Make your 3D and 2D objects stand out even more with effects like outline, glow, overlay, rim, and see-through.
Easy to use.
Every feature can be customized per object and you can combine them in any way you like.
There are several fill effects included and you can create your own as well.
You can exclude specific submeshes.
Allows you to affect an individual or group of objects.
Supports sprites and cutout objects.
Optimized for mobile devices.
Allows you to preview the effect in the editor without entering play mode.
Works with both orthographic and perspective cameras.
Use it in both HDR and LDR environments.
Comes with integrated C# classes and coroutines to help you create various effects without additional assets.
Includes built-in trigger classes.
Example code and usage is provided to make it easy to integrate into your project.
URP 2D renderer.
Unity version below 2020.3
VR and WebGL