D programs can make direct (=zero overhead) calls to C functions (like we do in C++). Which basically means you have access to any C library.

The D standard library is very dense (it makes C++14 standard library look ridiculously incomplete), so most things are available out of the box (threads, processes, filesystem, network, random, algorithms) ... in a portable way.

There's a Visual Studio plugin available, and I know VS Code has a nice plugin as well ( you need to install certain tools yourself in that case ), as well as other editors with their own feature set. There is also Dub[0] which is a build tool for D and gives you access to all sorts of D packages. I'm still a beginner to D so forgive me if my answer doesn't suffice.

[0]: https://code.dlang.org/getting_started