I've been using gopass for a long time as my password manager — with my GnuPG and Yubikey setup accessing my passwords on both my laptop and my colocated box is pretty transparently the same.
I randomly came across the fact that mutt will
do backtick
expansion in its configuration file. With that, I can keep my
Mutt imap password in gopass and have mutt fetch it with
set imap_pass=`pass mutt_imap_pass`