I understand them but which are the best in terms of low volatility vs. return? Is there such a thing?
In general terms, the wider the interest rate spread (larger the carry) the more volatile the pair. If you want something with relatively low volatility, you are talking one of the lower carry pairs. Of course there are no guarantees to any of it.
Thank you John for both answers (this one and the other about relational pairs)
Have a happy new year