Awesome, thank you so much. Like I said, you have no idea how much this helped me, I hated having tons of tags. I just wanted my tags to be simple genres and you saved me hours of time.
Here is a list of all the popular shelfs. http://www.goodreads.com/shelf
Some ones from page 1 that I know would help my collection:
'nonfiction': 'Non-Fiction', (sometimes it's tagged as 1 word)
'self-help': 'Self Help',
'historical-fiction': 'History, Fiction'