I'll nominate Ockam.
I've personally tried to build some fundamental constructs like transport agnostic e2e encryption and actor libraries, but never invested enough in them. Ockam is basically doing what I had attempted and failed at, but way way way better.
I saw their blog post the other day and I think it's quite cool. e2e encryption + actors is a super cool primitive for secure and resilient services. It reminds me a bit of the hashicorp stack, but as a library.
IMO definitely worth checking out - I think frameworks like this are extremely high potential.