Please note that some of these might not work for you if you are using Firefox browser. Another factor is also your WP version.
WYSIWYG editor
Bold: Alt+SHIFT+b
Italics: Alt+SHIFT+i
Link: Alt+SHIFT+a
Blockquote: Alt+SHIFT+q
Read More: Alt+SHIFT+t
Unordered List (ul): Alt+SHIFT+u
Ordered List (ol): Alt+SHIFT+o
List Item (li): Alt+SHIFT+l
Advanced Editor: Alt+SHIFT+v
Publish the Post: Alt+SHIFT+p
ins: Alt+SHIFT+s
del: Alt+SHIFT+d
Unquote/outdent: Alt+SHIFT+w
Undo: Alt+SHIFT+u
Redo: Alt+SHIFT+y
Edit HTML: Alt+SHIFT+e
Align Left: Alt+SHIFT+f
Align Center: Alt+SHIFT+c
Align Right: Alt+SHIFT+r
Ctrl+[number] to get various header sizes on highlighted text
Comment moderation shortcuts (navigation and editing)
Pressing j moves the current selection (light-blue background) down.
Pressing k moves the current selection (light-blue background) up.Pressing a approves the currently selected comment.
Pressing s marks the current comment as spam.
Pressing d deletes the current comment.
Pressing u unapproves the currently selected comment, placing it back into moderation.
Pressing r initiates an inline reply to the current comment (you can press Esc to cancel the reply).
Pressing q activates “Quick Edit” which allows for rapid inline editing of the current comment.