https://learn.go.dev lists many good resources.

The language spec at https://golang.org/ref/spec is a surprisingly approachable one-pager, it’s worth at least glancing over.

One of my all-time favorites talks is https://vimeo.com/53221560 from 2013. It shows off how Go scales by starting with a small task and continuously adding more requirements into the mix, while also demonstrating its concurrently support.