.NET Orleans
I spent some time learning dotnet core this year and with the slow-grind progress Microsoft has made it really does look like the technology stack might start to replace Java, Go, Rails, NodeJS, over the next decade. You can really <i>feel</i> Microsoft's experience in language development and enterprise software development coming together to provide better ecosystem ergonomics than other frameworks and toolchains.<p>Specifically I'm talking about tools like LINQ, dotnet core libraries, VS and VS Code integration, and the standard library and common library packages.<p>I still think it has a long way to go but its still a huge potential upside, which is to say nothing of how its coming to dominate the games industry as well.