A webextensions add-on (Firefox or Chrome) which lets one highlight text or a link containing an ISBN and visit the ISBN at Amazon.com.
The context menu options only appear when right-clicking qualifying ISBN links or selections, so it otherwise should not clutter the context menu.
Comes with two options, one to open in the same tab and another to open in a different tab. Either can be disabled (thus also avoiding a submenu).
- Allow specifying one's own URLs with substitute patterns (and with custom site title for context menu item label)