Seconding fetchmail. It’s configuration is quite elaborate for a whole bunch of situations. I’ve used it in a small office situation to pull email from their legacy ISP’s POP into an internal IMAP server, so they could have multiple clients sharing mailboxes. (And so they couldn’t set weak passwords on an internet-connected system :-/ )

This is the first thing I have heard from her about what she’s working on since she had her “wings clipped”. Hope she is still doing good…