Most of it happened 18 months ago when the Grand Alliance Order came out.
What was the Empire range is now a number of smaller factions
Collegiate Arcane - Beast wizard on griffon, the wagons, and battle wizards
Freeguild Guard - What it mostly the core state troops - swordsmen, spearmen, halberdiers, crossbowmen, hand gunners, greatswords, and generals
Devoted of Sigmar - Witch Hunters, flagellants, warpriests and war altar
Ironweld Arsenal - Engineers(Gunsmiths), Helblaster and Helstorm, along with a number of dwarf war machines, and the Gyrocopters. Sadly, the Great Cannon and Mortars are no more.