Reddit mentions of Go in Practice: Includes 70 Techniques

I guess it depends on how far along you are with Go. I used the following:

"The Go Programming Language" from Addison-Wesley, one of the authors Kernighan, co-authored the "C Programming Language" book. I'm kinda a programming language theory nerd, so I loved it. https://www.amazon.com/Programming-Language-Addison-Wesley-Professional-Computing/dp/0134190440/

I really got a lot out of "Go in Practice" from Manning Publications, especially liked the Concurrency + Concurrency Patterns chapters.

https://www.amazon.com/Go-Practice-Techniques-Matt-Butcher/dp/1633430073/

Since we almost always need some web programming these days, I used "Web Development with Go" for learning some basics and more advanced Go web programming. The code from the book is in github here: https://github.com/Apress/web-dev-w-go. It was good to get started with some APIs in the Go ecosystem.

Next I'm going to start on GUI development with go from Packt: https://www.packtpub.com/application-development/hands-gui-application-development-go

I've also been going through the O'Reilly learning path for Go from Rachel Roumeliotis. https://learning.oreilly.com/videos/learning-path-go/9781491958100/

Some others:

Profiling Go applications: https://www.integralist.co.uk/posts/profiling-go/

I always love the Java/JavaScript/Groovy/Ruby/Python "puzzlers" talks, check out the go puzzlers here: https://talks.godoc.org/github.com/davecheney/presentations/gopher-puzzlers.slide#1

First use on-line available resources mentioned already. as far as books go I'm reading "Go in action" at the moment and it has quite interesting approach, more problem based than tutorial.
https://www.amazon.co.uk/Go-Practice-Matt-Butcher/dp/1633430073/ref=sr_1_1?ie=UTF8&qid=1483963854&sr=8-1&keywords=go+in+practice