Nirmathi IrregularPCS: Inner Sea Magic
Features Replaced: Weapon/Armor Prof., Favored Enemy, Wild Empathy, Favored Terrain, Spells (note: the Ranger still receives 1 each of Favored Enemy and Favored Terrain)
Valid Archetypes to Combine with: Beast Master, Horse Lord, Infiltrator, Spirit Ranger.
Does not combine with: Skirmisher, Trapper
There is a bit of confusion regarding the entry on the PFSRD (I don't have the book). It trades the same feature away twice.
The class trades away Favored Enemy, and gets Focused Enemy.
The class trades away Favored Enemy, and gets Focused Terrain.
Focused Terrain should obviously replaced Favored Terrain, and that is what the combinations are based on.