I made a quick chart for some of the top coins that I'm personally interested in, to better assess correlations between them:
Interesting to see that BCH is king of fiat (most of it, 65%, takes place in Korea).
DASH, Monero and ZEC have the highest correlation to BTC.
I did this by hand. If someone knows of a site where this info is available dynamically, I'd love to see a link to that.