e.g.     for example
re:      concerning
ca.      about
AM       morning
PM       afternoon
etc.     and so on
N.B.     note well
b/f      before
cf.      compared
viz.     namely
q.v.     refer to, see (often used as a cross reference)
i.e.     that is
p.a.     per annum, each year
et al.   and others

http://www.abbreviations.com/

http://www.enchantedlearning.com/abbreviations/