When I took Pony for a test drive, the language itself felt pretty solid; the main obstacle was the tiny standard library.

When Pony's standard library grows to a useful size, it's going to be huge. The type system is gorgeous, the documentation is pretty good, and the community is extremely friendly and helpful.

It sounds like the type system is going to get more featureiferous; my understanding is that they are pushing towards actual dependent typing.

I wish I could target the browser too. Like my biggest problem is writing a front-end and backend in two languages. If I could do both in one, that would be such a killer feature.

Clojure and ClojureScript let you do this (albeit in Clojure)

IIRC, there is an implementation of Go that compiles to Javascript. https://github.com/gopherjs/gopherjs

I have been meaning to give it a try, but so far I have not found a good excuse to.

I know. I'm rooting for Kotlin for the same reason but Pony does look super promising.