ally
alter ego
analogon
associate
brother
close copy
close match
cognate
companion
complement
congenator
congener
coordinate
correlate
correlative
correspondent
counterpart
each other
equivalent
fellow
image
kindred spirit
like
likeness
match
mate
near duplicate
obverse
one another
parallel
parallelism
pendant
picture
reciprocal
reciprocatist
reciprocator
second self
similitude
simulacrum
sister
soul mate
such
suchlike
tally
the like of
the likes of
similarity
echo
analogical
analogous
analogy
homologue
homology
analog
lispro
contrast
digital
discrete
opposite