This is a paid asset, but now you can download 3D UI Elements Free.
Detail this asset from Unity Store: Original Link
3D UI Elements v1.1 (Latest version)
3D UI Elements includes 505 icons 3D, the most commonly used in the gaming industry. This package is very flexible to use. Variants of using this package, you can see in the screenshots.
Features 3D UI Elements:
★ The full 3D package elements of the interface. Includes a alphabetical, general, joystick, os, purchase, social, VR, system and more. A complete set of interface elements you can see in the screenshot
★ Each icon is presented in 6 styles: contour, filling, contour in rectangle, filling in rectangle, contour in circle, filling in circle
★ For each icon there are 3 variants qualities: Low, Med, Hi
★ All icons have prefabs
★ Free updates and additions for this package
You can try this package for FREE: LINK
Change log: LINK
★ You can supplement your 3D UI Elements additional package 3D Font Art Pack: LINK, which includes a set of 3D fonts (Text Mesh) in different styles
3D UI Elements on website: LINK
Product Catalog: LINK