SmartOS will run Linux distros in an LX zone, much like Solaris did. There are some limits around what syscalls are available, but generally most software works or a bug can be opened. There is support for Linux containers natively, but the last I checked only Docker v1 repos were supported. v2 is forth coming. Virtualization-wise, Bhyve is supported as is KVM.

If you are running open source, there are usually SmartOS packages in pkg src, which makes SmartOS zones a CPU/memory/security bargain. https://pkgsrc.joyent.com/