The two that I've settled on as being pretty powerful would be
1) A bank account with limitless money in it, meaning you just write any check or make any transfer or withdraw any amount of cash, which doesn't draw attention from anybody (like the IRS or the media)
2) The ability to control the health of any living thing including yourself. Granting immortality is probably against the rules, so this is the next best thing which basically ensures that you and your loved ones and posterity live full lives without succumbing to or being hindered by any kind of disease or other health issue. There is also the dark side of this power, which is to do the opposite of the above.