Field Guns, Field Artillery. Either are utter rape on legs, though arty moreso.
Abuse urban combat. Hide in buildings, use SRM infantry when something juicy trundles past.
Fire support. Field arty with an Arrow IV and homing ammo, and then a while pile of BA with TAG kit.
Fucking engineers are glorious if you're running double-blind. Demolition engies wiring buildings to blow, trench/fieldworks engies giving you cover wherever the fuck you want it.
Got a big-ass pile of water on the map, and the other guy has a taste for hiding? Beast-mounted infantry with Orcas and Laser/SRT support weapons. Swim rings around him.
Infantry can do all kinds of cool shit. Even more when you pair them up properly in Combined Arms formations.