I'm using the Ultimate Geography Anki Deck to complete my knowledge of countries.

I was motivated to do so my this LW Comment::

A few months ago I started using the Ultimate Geography Anki deck after performing quite abysmally on some silly geography quiz that was doing the rounds on Facebook. I now know where all the damn countries are, like an informed citizen of the world. This has proven itself very useful in a variety of ways, not least of which is in reading other material with a geographical backdrop.

This I fully second. Knowing some lesser known *istan countries has already been helpful in GJP.