I am looking for a repertoire to play against flank openings (1.nf3, 1.nc3, 1.c4 etc), based on my current opening choices, what do you recommend?

My repertoire includes:

As White:

1. English

As Black:

Against e4: caro-kann

Against d4:  Slav

I need a 'recipe' for everything else, also openings that cut down my study time are prefered.

Although as black I am also considering french aganinst e4 and QGD Tartakower vs d4, as you can see I am trying to build a repertoire based on related or similar openings, so what I need is ideas to fill in the blanks!.

1.c4 c6

1.Nf3 d5 2.c4 c6

1.Nc3 d5 2.e4 dxe4 (2.Nf3 c6)