As PA:
I use AT-PTs for anti air and anti infantry duties backed with LAAT/i-s and infantry inside said LAAT/i-s. If I want to autoresolve I use Dark Jedis only
As IR:
AT-PT again, since it is multi-role which I love, and AT-ATs and 1 squad of Specialists, since they can save units, even if you have no access to build pads. From Era 2-on also adding XR-85s to the mix.
As NR:
Speeders(or V-wings in late eras), T2-Bs and Armored Freerunners. The keyword is RUSH and rush hard
As EotH:
Megamaser Tanks covered by Flame Tanks and Mortar Tracked Armoured Tanks,1 squad of Kirovs for AA and AirStraekers as soon as they are available.