[e12e]

There was/is stackeless with a(n initial?) focus on game engines iirc:

https://github.com/stackless-dev/stackless/wiki

It got less attention than pypy, but might be more pragmatic wrt parallel perf. There's also some work in pypy to remove the GIL, but not sure if there's been any news on that lately.

[srean]

Stackless is wonderful, but its for concurrency not parallelism. Long time ago when I checked it out it was faster than go in concurrency but not so in parallelism.