That would have to be absurdly obscure. Case in point: even Hirokazu Koreeda’s “Distance” has translations available in most languages. I can’t even find art films that lack translations.

Lots of Chinese stuff that lack subs. Often it's only available on bilibili, too.

Ixcanul

Submitted and short-listed for Oscar nomination in the international film category, this Guatemalan film had Spanish subs for the parts delivered in Kaqchikel.

Never saw it after its initial release in Guatemala City.

I mean, even if something has no subs I think if it was important enough I would watch it anyway.

I've watched a handful of Takarazuka Revue play recordings with no English translation. They were adaptations of stories I was already familiar with, so that helped.

letermagô. That’s it.

I speak english well enough to not need translation/subs when watching obscure American movies :)

(Since you talked about foreign movie, I assume American movies count as foreign)