[JKT]

Scrolling - spacebar/shift-spacebar to scroll down and up one page at a time respectively.

Command-up/down to move through the tabs (N.B. there is currently a bug in the 5.6 sp whereby if a text entry field has focus, these don't work)

Browsing links - when the page has focus, press the first letter of the link (repeatedly for lots of links starting with the same letter). Note - another bug that has been present since the switch to WebKit with version 5.5 - pages don't get focus until you click on them.

History and Bookmark navigation - command-[ or ] to go back/forward in the history for a page. Control-F2 and arrow to the History and Bookmark menus to navigate your full History/Bookmarks (i.e. use Full Keyboard Access). Command-L to jump to the URL feed, type anything from the URL or title of the page you want to visit to search for it in the History/Bookmarks. Command-B and command-shift-H show you the Bookmarks and History pages respectively.

Press Enter if you want to jump to any pages labelled "Next" (useful for sites that shamelessly make you jump through multiple pages for a story to bump their advertising revenue).

Note - I haven't used Opera to know what it is you are asking specifically, but I'm guessing the answer to your last question (command-less keyboard shortcuts) is no due to the finding of links by typing the first letter.