I too wish there was more standard containers available in Go's standard library. However, I don't think there will be a collections package unless and until generics make it into the language. That said, there are some pretty good libraries out there:
Thank you for the links. I hope Go gets a good, solid container library that is reputable and widely used. And even better if that makes into Go proper some day.
- https://github.com/timtadh/data-structures ## I wrote this one.
- https://github.com/Workiva/go-datastructures ## this one is also popular.
- https://github.com/golang/go/wiki/Projects#data-structures ## big list here.