Unity is rebuilding the standard assets:
https://blogs.unity3d.com/2018/07/10/2018-2-is-now-available/
Standard Assets replacement
We have removed the 5.0 version of standard assets from the Installer in 2018.2 and are working on replacement packages for each part of the former prototyping pack. The first package (Standard Assets: Characters) will be available as a Preview soon after the 2018.2 release. It will contain a First-Person and Third-Person Controller integrated with Cinemachine, as well as a prototyping environment built with Probuilder. For details, watch for a blog post on the subject in the coming weeks. For those of you who need the legacy 5.0 package, it will remain on the Asset store.
For a link to some of the standard assets (they have variations) you can find it here: https://assetstore.unity.com/packages/essentials/asset-packs/standard-assets-32351
