Same but I found it a really bad choice for a Bash replacement

You have to reinvent the wheel every other day since the standard library doesn't come with much included

I see Penlight (which is Python-flavored, but also has some functional programming constructs) https://github.com/lunarmodules/Penlight , Moses if you like functional programming https://yonaba.github.io/Moses/, likely others, but you're right in that there's no standard, "opinionated" stdlib. No bigint support on LuaJIT etc.