Google Chrome	70.0.3514.0 (Official Build) dev (64-bit) (cohort: Dev)
Win 10

Since there is no way to focus a tab using the keyboard, you can't invoke the context menu. Keyboard only users are unable to do the following:

Duplicate
Pin tab
mute site
Close other tabs
Close tabs to the right

Please note that mute site has its own bug: https://bugs.chromium.org/p/chromium/issues/detail?id=818261