If you're like me and have decided you like your books complete and available for general release --or at least protected by more conventional consumer laws-- then there's some good news: Frog God/Necromancer Games' Fifth Edition Foes is apparently getting released April this year, and they have opened it up for pre-order.
Ordinarily I'd try to get this through the usual retail local outlet or online, but I've noticed Frog God seems to keep themselves exclusive, so it may not be possible to find a copy until some of their books trickle down to the secondary resell market on ebay.
Anyway, pre-order page is here. If it ends up being as good as the Frog God Tome of Horrors Complete then it should be well worth it. Given WotC seems to be aiming for a very lite official release schedule of actual RPG books, this could be a much needed follow-up tome to the Monster Manual.