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.