This is a paid asset, but now you can download Colorful Game Icons 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
Colorful Game Icons v1.0
Miscellaneous icons created using Affinity Designer software, you could use in your website, game, app, printing need or anyway you like.
Opens in Photoshop CS6 and upwards as well. However 100% customizable only in Affinity designer software. I have included icons in PNG Format (2 versions with and without background).
Highlights:
21 Icons created using Affinity Designer software
Neatly organized into layers and groups
100% Fully customizable and resizeable using only Affinity Designer software**
Available in .AFDESIGN | .PSD | .JPEG | .PNG formats
PNG icons are 512 by 512 px size
Icons are useful for Game Design, Web design, Mobile App Design
Each icon has 3 levels as shown in the preview images
only the 21 icons with above mentioned formats are included in the download.