minor 7th chord 3-ness

Hey Group! Anyone else out there fond of the minor 7th chord?
Considering a 3-note version such as d-f-c' (JI intervals 6/5:3/2),
can anyone think of any other common chord (in closed position) whose
component intervals' numerators (6 and 3) are in a 2:1 ratio? (And
the outer interval is 9/5, making for a niftly litte 3-ness...) The
only other chord I can think of (in the denominator) is the major
seventh chord 5/4:3/2.

For the chord d-f-c', could having the 2:1 ratio (of 6/5 and 3/2) be
equivalent, in a way, to having an octave in the chord (even though
its 6 and 3, and not a power of two), and thus imparting some sort
of 'chord energy"?

Thanks, Kelly