There's an arduino-compatible forth stack, avrforth.

It does require that you license code which runs on it as GPL, which I consider onerous. But it works! If that constraint suits you.

Same here! https://github.com/pmarreck/elixir-snippets/blob/master/rpn_... I found it fun, and it was actually super easy to implement a stack-based language interpreter in an immutable pattern-matching language like Erlang/Elixir.

It's incomplete because I haven't yet figured out how to define the defining character ":"...

Back in the C64 days there was a Abacus Forth but it cost was pretty high if I remember right $225???? I got a copy from the software store I work with as a teenager and got one at cost. It was great after coming from basic > assembly (Talk about your learning curves).