The Cleasby-Vigfússon entry [
http://lexicon.ff.cuni.cz/png/oi_cleasbyvigfusson/b0179.png ].

http://www.lexis.hi.is/corpus/leit.pl?lemma=fylgjur&ofl=&leita=1&flokkar=Fornrit&m1=fylgjur&l1=Leita&lmax=1

http://lexis.hi.is/cgi-bin/ritmal/leitord.cgi?adg=daemi&n=136142&s=168287&l=fylgja

The last list includes more or less modern examples, some with the
meaning 'placenta'. On the middle link I just searched for the plural
(searching for 'fylgja' on that one would have turned up lots of
examples of the verb "to follow/accompany".)