Keep an eye on USDJPY
Keep a close look at USDJPY.
Whether it is a mid-term duration from beginning of 2017 till present or over a shorter period from December last year, JPY is probably the weakest forex major against the USD.
So USD fell most of 2017 but USDJPY managed to go sideways for three quarters. Since December, DXY has fallen sharply yet USDJPY managed to stay in a consolidation pattern.
Should factors align in favour of USD strengthening, USDJPY could become the pair to go to.
To understand how to build/read an overlay, go to this story 'See relative strength, pick winning forex trade from an overlay'.