In the order of most to least useful:
⌘ L Place insertion point in search/title area Escape Clear current search Return Begin editing note, creating it if necessary Tab Move insertion point between text areas ⌘ K Select previous note in list ⌘ J Select next note in list ⌘ D De-select current note, restoring the search text ⌘ ⇧ V Paste clipboard as a new note ⌘ R Rename the selected note ⌘ ⌫ Delete the selected note(s) ⌘ ⇧ T Tag the selected note ⌘ G Find next occurrence of search text ⌘ ⇧ G Find previous occurrence of search text ⌘ ↩ Open any URL under the insertion point ⌘ ← Move to title-editing when at start of the note-body ⌘ → Move to the note-body when at the end of a title ⌘ ⇧ D Bookmark the selected note ⌘ P Print the selected note(s) ⌘ E Export the selected note(s) to other formats
Text formatting shortcuts:
⌘ [ (left square bracket) Outdent one or more lines ⌘ ] (right square bracket) Indent one or more lines ⌥ Tab Indent ⌘ T Make text plain; remove styles ⌘ B Embolden ⌘ I Italicize ⌘ Y Strikethrough