I posted these a couple of years ago and I found a few more to add to them:
Close a tab = Ctrl + W
New tab = Ctrl + T
Move to address bar = Ctrl + L
Move to Search engine box = Ctrl + K
Go to next Search engine = Ctrl + Arrow up or down
Open downloads tool = Ctrl + J
Add .com to address bar = Ctrl + Enter
Add .net to address bar = Shift + Enter
Add .org to address bar = Ctrl + Shift + Enter
Next Tab = Ctrl + Tab
Previous Tab = Ctrl + Shift + Tab
Find on this page = Ctrl + F