One of my professors at BYU created this very useful
website.
It indexes scriptures from LDS
General Conference talks (plus some other Church publications) from
1942-present. You can look use it 2
ways:
1.
Look up by scripture. You can look up a scripture and see who has
used that particular scripture in General Conference talk.
2.
Look up by speaker. You can look up a speaker
and see what scriptures they’ve quoted in their talks.
From this, I gather that President Monson’s most quoted scripture
in General Conference is:
D&C 107:99 “let every man learn his duty.” Quoted 16
times
However, if you count this next scripture when it’s either a
standalone verse or used with other verses then President Monson has also used
it 16 times”
D&C 18:10 “the worth of souls is great in the sight of
God”
I did pretty thorough search but you may find something I
missed that was higher. Take a look and
use it to look up your favorite scriptures and speakers.