This is a paid asset, but now you can download 100 Modern Icons Pack 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
100 Modern Icons Pack v1.0
There are 100 distinctive icons in this Awesome Icon Bundle that you will adore!
All the icons also come with a commercial license allowing you to use them for multiple personal and commercial projects.
What you will get:
100 Unique Icons
Extended license – create and use as many of these icons as you’d like on your own personal projects as well as any commercial ones for clients.