I'll do a little self promotion here: https://pisc.junglecoder.com
It's a stack-based concatenative scripting language implemented in Go. There are also Go implementations of LISP (zygomys) and Lua that may well be worth looking into, if you'd like to see how one builds a language in Go.
Otherwise, the standard library is always a good way to find out about things that you didn't know existed, or forgot after reading the standard.
Otherwise, the standard library is always a good way to find out about things that you didn't know existed, or forgot after reading the standard.