Retrievers
----------

fetchmail
getmail4


Filters
-------

procmail - mda
imapfilter
yample
mailfilter - mda?
maildrop - mda

Syncers
-------

imapcopy
imapsync
isync
mailsync
offlineimap

Converters
----------

mailutils
mb2md

Proxyies
--------

imapproxy
perdition