Calvary

P.S. Some of these are not horses. ehhhhhhhhhhhhhhh

5 OS: Horseman

7 OS: Cateract

10 OS: Knight

15 OS: Epic Knight

20 OS: Curriamar

30 OS: Tank

50 OS: Medium Tank

70 OS: Battle Tank

100 OS: Epic Battle Tank

150 OS: MBT Mk3

200 OS: MBT Mk4