There's also the official SSH client that is a NaCl version of OpenSSH, I've been toying with it since it seems kind of superior to PuTTY on Windows.
You should try hyperterm, it's based on the chrome ssh NaCl version shell with support for plugins on top https://hyperterm.org/
They will probably port that, and Hangouts, Google Drive and others, to extensions, I think.
ServiceWorkers allows installing apps on Chrome or on the desktop so hangouts and drive could use it. Not so sure about ssh and what's going to happen to NaCl.