To show addition:
a second point
again
and
also
another
as well
besides
first, second…
for one thing…for
       another
further
furthermore
in addition
moreover
next
or/nor
too

To compare:
also
by comparison
equally
in the same manner/in
       the same way
likewise
similarly
than

To contrast:
although
but
conversely
however
in contrast/by contrast
nevertheless
nonetheless
on the contrary
on the other hand
rather
still
though
unlike
whereas
yet

To give examples:
for example
for instance
in fact
in particular
namely
particularly
specifically
such as
that is
to illustrate/as an
       illustration

To emphasize a point:
above all
certainly
chiefly
especially
indeed
in fact
in particular
more/most importantly
primarily
unquestionably

To restate a point:
again
in brief
in effect
in other words
in short
in simpler terms
that is
to put it another way
to repeat

To summarize or conclude:
in conclusion
in other words
in short
in summary
that is
therefore
to sum up

To indicate logical relationship:
as a result
consequently
for this reason
if…then
since
so
therefore
thus

To introduce a qualification or concession:
admittedly
after all
all the same
despite
doubtless
even if/even though
frequently
generally
granted
in a sense
in general
in spite of
it is true that
naturally
no doubt
notwithstanding
occasionally
of course
otherwise
provided
surely
to be sure
unfortunately
usually