So, this came up it another thread, and it bothers me.
It also has likely been addressed already as I'm a decade late, in which case I missed it, my bad.
Anyways : Favored Enemy needs a subtype for Humanoids and Outsiders, as we know.
We have a list, which includes Humanoids (other subtypes), but nothing of the sort for Outsiders, who seem therefore limited to native, specific elemental and aligned subtypes.
Now, not being able to specifically hunt demons or azatas isn't much of a problem. A bit disappointing, at worse.
But there are major outsider subtypes that fit in none of those, such as aeons and psychopomps ... Some even have no subtype at all, which is another issue.
Now, I know I'd houserule they - and any subtype - can be chosen as well, but RAW doesn't support it, apparently.
As an example, rebelling against Death itself and its agents, choosing them as your Favored Enemies is too flavourful to not be allowed. Followers of Mahathallah, or just good old Urgathoa, the Whispering Way or any of that sort, should be allowed to pick psychopomps. As should anyone angry enough at death, which is probably not uncommon.
Likewise, not being fond of the balance enforced by the oh-so-mysterious and cryptic aeons isn't that hard to imagine in a multiverse made of extremes.
The ones without a subtype to begin with are probably specific - and uncommon - enough that if they're relevant to your campaign I'd likewise houserule them as their race being their own "subtype" or something. But even a simple (any other subtype) correction wouldn't be enough for those, admittedly rare, corner cases.
Is it an oversight ?
Has there been a correction I'm not aware of ?
I'm mostly surprised the crb had provisions for humanoids, yet no such for outsiders : the way these things go, 3.x being what it is, new things were bound to come up.
As a sidenote, it's worth noting the Bane property mostly does not have that issue, as it allows any subtype.
Still some exceptions, but again, very rare and specific.
for a moment I thought the title was "Outsider Flavored Enemy"...
Devils get you that wonderful smoky BBQ flavor. Angels taste like candy. No one wants to try the qlippoth to find out what they taste like.