Terminology:
The movement axis of the input device will be in X & Y space, a standard Cartesian plane. This can be a gamepad or a mouse, it doesn't matter.

The camera itself will be described in terms of Pitch, yaw, and roll. However, pretty much(?) only 6DOF games allow roll, so it will be simpler to describe it in terms of pitch and yaw unless otherwise required.

We do not need to specify the handedness of the coordinate system here.
That is, +Yaw would look left from its perspective. +Pitch would look down.
I'll probably format this into a table eventually.
"Pitch up" in this context would mean -Pitch — therefore, Look Up — FYI.
Insomnia: The Ark
Can invert camera controls? NO
Pitch: N/A
+Yaw(Look Left): -X (Mouse Left)
-Yaw(Look Right): +X (Mouse Right)
Orbit: No
Enclave
+Pitch(Look Down): -Y (Mouse Down)
-Pitch(Look Up): +Y (Mouse Up)
+Yaw(Look Left): -X (Mouse Left)
-Yaw(Look Right): +X (Mouse Right)
Orbit: Pitch+Yaw? Need to test Yaw.
Notes:
Camera pulls out when looking down, and pulls in when looking up.
Final Fantasy XI
Can invert camera controls? YES
+Pitch(Look Down): +Y (Mouse Up)
-Pitch(Look Up): -Y (Mouse Down)
+Yaw(Look Left): +X (Mouse Right)
-Yaw(Look Right): -X (Mouse Left)
Orbit: Pitch+Yaw
